How to Send Text Messages From Facebook
Messaging is one of Facebook's older features. This feature allows you to send a private message to another Facebook member, much like an email. What many users don't realize, however, is that they can also send text messages from Facebook to users who have tied their cell phone number to their Facebook account. You can send a text message via Facebook in just a few steps.
Sign on to your Facebook account (see Resources).
Click the chat bubble icon next to the Facebook logo, then select "Send a New Message."
Type the name of the person you'd like to send the message to in the "To" field and enter your message in the "Message" field.
Check the box next to the tiny cell phone icon in the bottom right corner of the "New Message" window. By checking this box, you can also send the message you've written as a text message to the recipient's cell phone.
Click the "Send" button to send the Facebook message and text message.