To send SMS with password reset for a user or a bunch of users login to the MSPControl and click on Users (User Organizations),
or go to Organization > Organizations > Users.
You will see the list of all users. If you have many, it might be a good idea to use Search form in the right to find the one you need. You can choose whether you want to search by Display Name, E-mail Address, Domain Account, Account Number, or Login.
Once you found the user(s) you were looking for, select them by checking the corresponding check-boxes in the left.
Then select Send password reset SMS in the drop-down menu Actions, and click Apply.
You will see a notification Action has been successfully performed.
Note: Make sure those users have a phone number added in their profiles, and, more importantly, check with your administrator if you have an integration with SMS service.