First you need to activate the Invite User Service. This is done by following these steps:

1. Open up the app in Aquro App Studio
2. Navigate to the Development pane
3. Expand the Backend services node in the left treeview
4. Click on the  Invite user service node
5. Click on the ACTIVATE button

Once the service is activated you may configure the service:

Email template
The invitation email sent to the user is based on a email template that uses the Email service (read more about the email service here). When the invite user service was activated a default email template was created. To modify the email template follow the instructions here. For a full list of all the values supplied to the email template read this article.

Generate password
You may select if you want to pre-generate a password for the invited user or if the user should register his user account as a regular new user.

If you chooses to generate a password the new user only have to sign into the app with his email and password.

When you are done configuring your service click on the SAVE button to save your changes.