Want to send a private message to a Facebook friend? This guide will show you how to do it.
Once you have logged in to Facebook, go to the profile of the Facebook friend that you want to message. You can do this by looking for the name of that user in the search box at the top of your page. Once you are on his or her profile, click on the “Message” button, which is near the top right hand corner of the screen.
Once you have done that, you will see a small window with the name of the user you are messaging near a “To:” label. Write your message in the textbox near the “Message” label, and finally click on the “Send” button.

This way your message will be sent. The person to whom you sent the message will be notified of this by email the next time he or she logs in to Facebook.
How to Use Facebook >> Friends and Users >> How to Send a Private Message on Facebook
Want to send a private message to a Facebook friend? This guide will show you how to do it.