This setting can only be managed by an admin.
To manage the users of an entity go to Settings > Users. Here you can see and edit all users on the entity.

How to add more users
To add a new user, follow the below.
Go to Settings > Users
Click on Add users up to the right
Fill in the name, email, which role you want them to have, and if they are to be part of a Team
Toggle in if you wish to add a user without sending out a confirmation email to them
Click Save
Done!

How to manage existing users
To manage an existing user, follow the steps below.
Go to Settings > Users
Click on the name of the user you want to manage
Ex. add them to a team, user role or their statusClick Save
Done!

Please note!
You can't change the email for an existing user. The user can change the email themself under My profile.