Settings -> Usersand click on
Create Invitation Link.
Settings -> Userspage and click on the tripple doc button next to the user.
Editmenu item. You will be presented with a screen to update user's information.
Deactivatemenu item. When a user is deactivated she will no longer be able to access the organization. The data that's linked to the user (comments, objectives, etc.) will remain intact.