If you have important news that you need to get out quickly, Facebook enables you to send a message to up to 250 people at once. The process is the same as sending a message to one person -- and there is a trick you can use to do it quickly. If you want to send a lot of messages to everyone, consider creating a secret group. Posts you send to a secret group are just as private as Facebook messages, but your friends have the choice to opt in or out of the group rather than muting you or marking your messages as spam.
Quickly Messaging Everyone
Log in to Facebook and click the "Messages" icon at the top of your home page, just as you would to message one person.
Type each friend's name and select your friends from the list that displays when you type. If you literally want to send a message to every friend on Facebook, you can do that quickly. Just type "a" and click a name, then keep typing "a" and clicking a name each time.
Type "e" when names no longer appear when you use "a." Click every name using the letter "e" until the list is blank, then use "i," "o," "u." Unless your friends don't have vowels in their names, this system should quickly cover everyone. Type your message and press "Enter."
Creating a Secret Group
Go to your Facebook home page and scroll down to the Group section in the left menu. Hover the cursor on the right side of the word "Group" and click the "More" link that appears. Click the "Create Group" button.
Type a name for your group in the "Group Name" field. Click the "Secret" option so that no one except members of the group can see your messages. Start typing your friends' names in the "Member" field. To add everyone to the group, click every name that appears in the Suggestions list. Click the "Create" button.
Select any of the icons to make your group easy to find on your home page menu, or skip this part. Icons aren't a requirement. Click "OK" to send invitations to all your friends. They have to accept the invitation before they can see your messages.
Type a message in the "Post" field and click the "Post" button to send it to everyone who accepted the invitation. Posts to a group appear in your friends' news feeds. Add a description for your group if you want, but this isn't a requirement. To send additional messages, you can find your group's page in the Group section of your home page.