How Getting user mobile numbers from Gravityforms?

If you want getting user mobile numbers from Gravity form, you can write a hook for this job.

For example:

add_action("gform_after_submission", "after_submission", 10, 2);

function after_submission($entry, $form){
	// Get mobile number
	$mobile = $entry['YOUR_FIELD_ID'];

	// Insert to DB
	$subscriber = new WP_SMS_Subscriptions();
	$result = $subscriber->add_subscriber('Name', $mobile);
}