Our product allows citizens to text-to-join the system with a keyword. They do not have to create an account or log into the system to do so.
A template example is attached to this article, and you can call your Client Success Manager or contact your Support team for assistance in customization. A customizable version is also attached if you would like to make your own modifications.
Please see our article Text in to Join a Group for instructions on how to set-up Text-In options.