If you're an Org admin, you are able to perform the following user management operations:
Org Admins can assign roles to both users and apps. To assign a role to a user:
You can also change the roles for a user by clicking the More button in the top right on the user details page.
As always, utilize "principle of least privilege" best practices and only assign necessary roles. Apps having the Org Admin role, for example, will have full rights to manage users, apps and resources in your Org.
You can also activate and deactive a user on the user details page.
Deleted user accounts cannot be restored.