Once your phone number has been enabled for SMS functionality, you will be able to send and receive SMS text messages via your email.
To send a text message:
XXXYYYZZZZ is the 10 digit phone number you wish to send a text to
Subject: Anything (your email will determine the from DID)
Body: The content of the text
To receive a text message:
When someone sends a text message to your SMS enabled phone number, you will receive an email from XXXYYYZZZZ@sms.loopphone.com where XXXYYYZZZZ is the 10 digit phone number that sent the text message. The subject will be "SMS Message" and body of the email will be the text message that was sent to you.
You can just reply to the email to send a text message back from your phone number.