Please follow this guide if you'd like to invite a user or support to your organization temporarily. You need to have administrator rights to do this.
Invite users with temporary access to the organization
First, click "Administration" and then "Users" in the left menu.
Then click the "Invite new users" button.
Fill in name and email, check the option "Temporary access," and select the date when access should be removed. Then click on the "Add" button.
If support has asked you to invite someone, ensure that the authorization level is Administrator and the specified email address has been entered.
Then, send the invitation by clicking "Send Invitations".