Удаление учётной записи пользователя
You can add multiple user accounts to your computer. If somebody is no longer using your computer, you can delete that user’s account.
Для удаления учётных записей пользователей нужны права администратора.
Go to the Desktop and start typing Users.
Click Users to open the panel.
Нажмите Разблокировать в верхнем правом углу и затем по запросу системы введите свой пароль.
Select the user that you want to delete and press the Remove User... button, above the list of accounts on the right, to delete that user account.
Each user has their own home folder for their files and settings. You can choose to keep or delete the user’s home folder. Click Delete Files if you are sure they will not be used anymore and you need to free up disk space. These files are permanently deleted. They cannot be recovered. You may want to back up the files to an external storage device before deleting them.