Note that for each case, you can select either the simplest form of the URL (containing only your username) or the one including the id_string of the form.
The latter works without specifyin the SMS Keyword in front of every message.
You would use it when your SMS Setup/Provider is used for only one form.
Use the Generic SMS API to write your own wrapper around Formhub.
STATUS: One of ACCEPTED, REJECTED, PARSING_FAILED MESSAGE: Either an error or success message. Suitable for end user. ID: Only if successful. A unique ID of the submission.