You can add new users in the Manage Users tab under the My Account menu.
Only Account Administrators can add new users. The number of users that you can add depends on your current license. If you need to add more users, please contact your Customer Success Manager or email@example.com and we'll be happy to help.
If you have reached the user limit, you won't be able to invite new users but you can review your pending invites and cancel the ones that are no longer relevant: