The Send an SMS button needs enabling in User Profiles by following the steps below:
Enter the User Profiles program and ensure the Autorisations tab is selected.
Find and click on the User who requires this functionality.
Navigate to the Actions section and ensure the Send SMS box is ticked.
Click SAVE and EXIT.
If you or your System Administrator does not have access to User Profiles, please raise a new case online and reference the title of this article.