The ClickSend SMS add-on needs to be installed and activated to see the features mentioned in this this documentation.
How To Use the Ninja Forms ClickSend SMS Add-on:
The ClickSend SMS add-on for Ninja Forms enables integration with ClickSend for sending text messages using SMS (Short Message Service). This has all sorts of uses, like texting notifications on submission, or thank you notes.
Connect Your ClickSend Account
Login to ClickSend
Copy API Key
Add Username and API Key to Ninja Forms
Setup the Form to Send a Message
Add the CickSend SMS Action
Map the phone number and message.