Sending SMS's costs somebody money: so finding a truly free SMS sending service is going to be down to you and Google - the chances are that you won't find one that will let you send more than one or two per hour, or will have other restrictions on you.
Quote:
i dont know what is this section "What have you tried?"
It's a place for you to show us that you have made an effort to do at least some of the problem yourself, and to let us know what you have tried and why it didn't work - so we don't repeat the same work over again.
Not putting anything in it says "I can't be bothered to do this task - you do it for me" - which is both rude and unlikely to help you get a solution handed to you...