How To Manage Users in Linux
User management may not sound like the most glamorous task, but nonetheless it is an essential part of a busy system administrator’s job. Creating new users, be they your family, friends or co-workers involves giving them the correct permissions, and managing what they can do. All of this can be done via the GUI and the terminal and in this how to we will show how.

All the commands in this how-to will work on most Linux machines. We’ve used a Ubuntu 20.04 install but you could run this how-to on a Raspberry Pi. Some of the how-to is performed via the terminal. You can open a terminal window on most Linux machines by pressing ctrl, alt and t. When working through this how-to take extra care when you have multiple users set up that you are selecting and deleting the correct user accounts!
Add A New Linux User Via the GUI

For most, user management via the desktop is more than sufficient and thankfully most Linux distros have this down to a tee.
To add a user via the GUI
1. Open the settings application, scroll down the list and select the users tab.

2. Click on the unlock button and enter your password. Editing these settings requires us to unlock them via a password. This helps to avoid accidents when working with user accounts.
3. Click the Add User button to open a new dialog box.

4. Add the new user’s name. The tool will suggest a username, but you are free to change this. You can either add a password for that user at this stage or you can allow the user to set their own password when they first log in. When done, click Add to save. You will be prompted for your password to confirm the creation of this user.

5. Optional step: Give users additional privileges by clicking the administrator tab as you create the new user, or by toggling the administrator button if the user account is already created.

6. Log off and switch users to the new user account. You should notice that they have their own Home directory and that any applications will use the configuration settings for that user.
Read more: https://www.tomshardware.com/how-to/manage-users-in-the-linux