You are only able to receive text messages at the one mobile phone number on your account settings page.
Step 1) Log in and go to the Account Settings tab of your user dashboard.
Step 2) Click Add Mobile Phone if your phone number is not already there.
Step 3) Enter your phone number and click Submit.
Step 4) Check your phone for the validation code.
Step 5) Enter the validation code and click Submit.
Step 6) Check the box with your phone number under Notification Settings.