Follow the below mentioned steps to Add Signature in SMS using DO SMS Panel:
Login into your DO SMS Panel
Click on the "Send SMS" option available in the Left Side Menu
Click on the "Settings" icon displayed on the right side of "Schedule SMS" option
Tick the check box which states "Add Signature" and type the characters that are to be Stored as signature and press the close button (Note: Signature will also be counted as SMS characters and will affect the credit count)
See our article on the process of CreatingSMS campaigns: Click Here