If you have text-enabled numbers in your account, you can send and receive text messages (SMS and MMS) through your text log. This article will cover sending or replying to single text messages (messages with a single recipient). For more information about bulk text messaging, see the full article here.
Text messages are broken into units of 160 characters for the purposes of billing. You may compose messages of up to 800 characters at a time using this interface, but every 160 characters will be billed as an individual message. Special characters may use more than a single character when composing a message.