Single user account on a shared computer can be a security issue? Using multiple user accounts in Ubuntu is a powerful way to improve both security and workflow organization. Separating work documents from personal files, restricting access to sensitive data for different users, and simplifying collaboration with colleagues. Most importantly, using a single root account for everyday tasks creates a significant security risk. Accidental data deletion or accidental compromised program installation with root privileges could have devastating consequences.
Adding new user
Set your username.
sudo adduser username
When adding new user you can just add the password and skip other requirements like complete name and address and other things if thats not necessary for you.
Removing user
sudo userdel username
Delete everything of the user including files
sudo userdel -r username
Grant the user sudo privilege ( user can install and and change everything)
sudo usermod -aG sudo username
To remove sudo privilege
sudo deluser username sudo
Update username of a user
sudo usermod -l newname previousname