Click on SMS menu on the left pane of the window to send the SMS to the user
Enter the following to send a message to the user
Sender ID:- Enter the sender ID
Send the message by selecting any one of the following options
New No- By entering the new number of the user
Select One- Select any one user
Select by Username- Select first username and last username
Select All- Select all the users
New No:
Select the new number option to send the message to any new number. Enter the new number and the message as shown in the below screenshot.

Select One
Enable the Select One option to send a message to any one user. The mobile number of the respective user gets popped up and enter the  message as shown in the below screenshot.

Select by Username
Enable the Select by Username option to send the message to two users. The mobile numbers of the first username and last username are popped up and enter the  message as shown in the below screenshot.

Select All
Enable the Select All option to send a message to all the users. “All numbers” gets popped up and enter the message as shown in the below screenshot.

After selecting any one of the above methods, click on Send SMS to send the SMS.