How do I text to someone's cell from my computer?

I have tmobile. I received a text message on my cell without senders number. How do I find senders info. thks?

• i received a text msg on my cell phone bbut it had no sender information. so I thought it was sent from someones computer. how can I find out who sent me this text message. thanks- i really appreciate your assistance. houses

• Answer:

  Maybe the sender has his ID blocked, but if the message is illegal or abusive you could have the police get the telephone company to trace it.