How to mention someone on facebook?

If you want to mention your friend in your status update or commenting on a post then type @ first then followed by your friend name for example your friend name is KILLER then if you want to mention KILLER then type @KILLER, then it will show some suggestions under that, select KILLER that's it or if you want to tag any of your friend in a photo then select that photo and select tag photo in right below corner of that photo and in the pop up box type your friend name and select ok. Have a nice day :-)

Are you talking about tagging someone in a post? I'm not sure if it works on phones but I know on the comp you just type @ before typing the name in. Normally when you put @ and the 1st letter of their name it brings up a list of your friends to choose from.

I am assuming you mean how to tag someone in a post?!? If so, type @ and then person's name. When it pops up, click on the persons name and then post.

It will notify the other person that you've tagged them in your post.

didn't know you had to put @ just type their name with capitals at the start

You add @ in front of their names.

Do you mean the "@" thing ?