Steps:

1. Go to Settings | Security | Users. The account users and the associated details are displayed 
2. Click Invite a User.
3. Complete the details and send the invitation. 
4. When the invited user has created a password and activated the account, the approved checkbox will be selected.
5. To change the user role, click on the role name and select the required role.

Additional Information:

Ensure that you have the necessary user license or have purchased more licenses to invite user