You can use one-way text messaging for communication.

When you have a text messaging plan, and you enable one-way texts, you can send texts to individuals from all the places in Realm where you can currently send emails. This includes queries, pathways, dashboards, team rosters and group rosters.

You can assign users with responsibilities who can send one-way texts, and view text usage by each user. You can also view a history of individual one-way texts in the My Communications section.