It so happened, any operating system (Android is not an exception) is built from three basic components:

• Bootloader - checks the system (compliance of hardware and software) before launching the kernel.
  
• Kernel - a set of commands and executive scripts, also contains drivers.
  
• Interface - A utility or set of utilities for interacting with the user’s kernel and vice versa. It includes: GUI (graphical interface of interaction), connecting interface components with the kernel, etc.

All this together is the operating system.

Let's look at the concept of "operating system administrator".
Any file on the disk always has three basic permissions:

• R / W (Full access to read and change the contents of the file / folder)
  
• RO (Read access to the file / folder, changing the content is prohibited)
  
• NA (Cannot access file / folder contents)

Because of the fear, before some inappropriate, and some will be able to access system files and / or personal information, it was decided to distribute the so-called "permissions". For example - we create a user (account) "Vasya Pupkin". With the one who goes under his registration data will be full access (if it did not limit his computer / network administrator) to its folders and files, but not having the user's rights "Administrator" on the computer, our dear MR. Pupkin will not be able to even change the screen resolution!
From this it follows that it is an account with full R / W access to the entire system that has the ability to make any changes in its core and / or work with other important components of the operating system.
Android is based on the Linux kernel. On NIX-type systems, the “Administrator” account is referred to as the “root user”, in English - root user or abbreviated - root.
As we said earlier, in the operating system based on the Linux kernel there is such a thing as a super user, super user, also known as root user, who has full access to the components of the operating system, including the kernel.
Android is no exception, although a bit "neutered." One of the effects of this "castration" is the removal of the local super-user, that is, the complete absence of an account with full access in the system (for the sake of the user's safety, as they say). For one reason or another, we want to get it. We make manipulations, "sew" SuperSU or Magisk and voila, the necessary changes were made, our super-user account was created / activated.

As we already know, our super-user account was created / activated, and for this, certain changes were made to the system. Namely - some files were added that contain a certain program code, which allows us to use these privileges.
As we know, when updating the system by air (OTA), the update script checks the integrity of the system image and, depending on this, gives or does not give us the opportunity to update the system. In the presence of files confirming the presence of root-rights in the system, our OTA-Updater on many devices either does not work, or leads to incomplete / incorrect installation of the update and, as a result, to the "brick" (not with us, with us or the root will fly off , or the OTA update is simply not installed).
To understand this better, consider the two options for getting root-rights:

• System root - changes are made directly to the system, bypassing the kernel. In our case, the application for managing root rights is installed in the / system / app folder, a binary file is installed in the system and several symlinks are created.
  
• Unsystemable root (Systemless root) - changes are made to the kernel, allowing the system to initiate the image of SU.IMG when starting the system, which is in / DATA. After loading the system in the root directory, we see the / SU folder, which, according to the tree structure (placement of folders and files inside), partially repeats the structure of the / System folder structure. In these folders, the necessary files are stored, without getting into system folders. Unsymptic root was invented and implemented with Android 6.0. The idea was in creating the opportunity to make OTA-updates without losing root rights. In fact, this does not happen, changes in the kernel disappear, as the kernel is overwheed when OTA update.

As for our device, the main utility to get root is Magisk. Magisk (haphazard) - a new development, the main chip, which is the ability to hide root rights from banking applications and not only.

This question suggests itself for a long time.
Where to us to "attach"? Recovery is part of what? What does it affect? What influences him?
Recovery is a separate micro-under-operating system that uses our bootloader and has its own interface.
Basic versions of recovery (for example, those with firmware), although they have very limited functionality, are also very powerful tools that have access to many areas of our main operating system, Android, and allow you to perform actions on them WITHOUT logging into the operating system itself. For example, delete the contents of the / Cache or / Data sections.
More advanced versions of recovery (CWM, TWRP, Philz, etc.) have advanced functionality, which, together with access from the outside, gives us a very powerful tool.
For example, we can edit system files, delete passwords, save / restore entire system partitions without being in the system.
Note: with the help of some manipulations in recovery, the device can be brought to complete disrepair. Therefore, it is desirable to understand what we are doing and why.

Among the advantages are the following:
• accessing and modifying system files and applications
• the ability to install many applications that require root for their work
• installation of third-party firmware and mods
• remove pre-installed programs and other garbage
• activation of many additional features of Android
• increase in productivity and autonomy
• ad blocking
• distribution of the Internet without restrictions
• Viper4Arise (best sound)
What are the disadvantages and dangers of obtaining superuser rights?
• it deprives you of a guarantee (in fact, all signs of this operation can be eliminated)
• it will be slightly more difficult to receive OTA updates

1. On the phone, go to "Options for Developer" and enable "Factory Unlock" (as in the screenshot), also check the "Debug USB" option, it should be enabled:You can also enable the advanced reboot option and reboot into Bootloader (Fastboot).
2. Enter Fastboot mode, for this you need:

• Turn off the phone.
  
• Press the volume key up and the power key, after a few seconds, the screen should say "fastboot" or "fastboot mode".
  
• Connect the phone to the computer using a USB cable (preferably the original one that comes with the phone).
  
• I have Windows 10 Creators Update and above

  Then open the command window: open the folder where the ADB is located, for example C: \ Android>in the free space of the window, press Shift + Right mouse button>"Open power shell window". In the command window write the command:

  CMD

  Go to the "last point" in this list.
  
  
  I have another OS

  Then open the command window: open the folder where the ADB is located, for example C: \ Android>in the free space of the window, press Shift + Right mouse button>"Open command window".
  
  
• At the command prompt, enter the following code:
  
  fastboot devices
  This command will show the list of connected phones.
  If the serial number of your phone is highlighted, you can proceed
  
  If not, you need to check the connection of the phone / driver.
  

3. Enter the following into the console:
On the phone, we confirm the unlocking in the menu that appears (control in that menu is carried out using the volume and power keys), selecting the topmost item - "YES".
4. Next, your phone will restart, you will need to go through the initial configuration of the phone.
5. Activate developer mode again and enable the "Debug USB" option.
Important ! You can not block the bootloader (fastboot oem lock) when recovery TWRP is installed, otherwise there will be a brick!

It is not recommended to install SuperSU, as it does not work correctly on Oreo.

Download the latest version of TWRP to your computerfor 5orfor 5T, put the file in the command line utilities folder: adb.exe, fastboot.exe and rename it to twrp.img
Enter Fastboot mode, for this you need:

• Turn off the phone.
  
• Press the volume key up and the power key, after a few seconds, the screen should say "fastboot" or "fastboot mode".
  
• Connect the phone to the computer using a USB cable (preferably the original one that comes with the phone).
  
• I have Windows 10 Creators Update and above

  Then open the command window: open the folder where the ADB is located, for example C: \ Android>in the free space of the window, press Shift + Right mouse button>"Open power shell window". In the command window write the command:

  CMD

  Go to the "last point" in this list.
  
  
  I have another OS

  Then open the command window: open the folder where the ADB is located, for example C: \ Android>in the free space of the window, press Shift + Right mouse button>"Open command window".
  
  
• At the command prompt, enter the following code:
  
  fastboot devices
  This command will show the list of connected phones.
  If the serial number of your phone is highlighted, you can proceed
  
  If not, you need to check the connection of the phone / driver.
  

Enter:

Use the volume buttons to select the item "Recovery" and briefly press the on / off button once. Now your task is to wait until the question described below appears.

• A screen will appear asking you if you want to allow system modification (If you want to allow system modification?). Swipe right to allow changes.
  
• Download the latest version of Magiskfrom here.
  
• Throw the Magisk on the phone, install the zip in twrp.
  
• Open Magisk Manager, give root rights, enable hide and non-system hosts in the settings of Magisk.
  
• Reboot your phone.
  
• Open Magisk Manager and check that the SafetyNet tab has passed.
  
• Go to the next item.

-What is it for ?
-It will allow you to restore parameters such as: IMEI, S / N, GPSID, WIFIMAC, BTMAC, etc. in case of their loss. Without these parameters, the phone turns into an almost useless thing.

Everything that is listed here is exclusively my IMHO, i.e. This is a complete set of applications / mods / utilities that I need for normal (convenient) work, however, I will try to be as unbiased and objective as possible. If any of the following does not work for you, then before writing an angry message to me in QMS, I strongly recommend that you familiarize yourself with the topic of software that is not working for you.

• Solid Explorer File Manager- minimalistic and stable file manager.
  
• Zarchchiver- A very powerful tool for working with archives.
  
• Drivedroid- a very good thing for sys. admin. Allows you to mount images and use the phone as a bootable usb-drive.
  
• AdAway- the best ad blocker. The basis of his work is the automatic editing of the hosts file.
  
• Macrodroid- the most functional and usable "automator".
  
• Termux- just a good terminal, with the ability to conduct several sessions simultaneously.
  
• Toggle Network Type 5.0- A very handy widget for quickly switching the type of network (2G, 3G, 4G).
  
• Viper4Arise- the best audio mod, the heir to ViPER4Android. In fact, it is a system equalizer.
  
• TTL Master- allows you to bypass the ban on tetering your operator. It works only with kernels that support ttl change in iptables.
  
• YouTube ad-free- I recommend to install the nodpi version.

Lastly, I want to say that I highly recommend you not to use: Xposed, Greenify, Naptime, Titanium Backup, ForceDoze, MicroGMS, various cleaner'y, Disable Service etc.