Apex Legends is a free-to-play multiplayer game that is available on PlayStation 4, Xbox One, and PC. Listed below is how to invite friends to play on each of those platforms.PlayStation 4 & Xbox One
Playing with friends using either of these two consoles is simple enough, you just need to add players to your PS4 and Xbox One friends lists and invite them from there.PC
Inviting friends is not straight forward if you are playing on PC. To add friends on Apex Legends will involve going through the Origin Launcher (click this link to download)
which will need to be installed onto your PC. Once you have downloaded the software you will be able to access a 'Friends' tap on the top right of the screen which will allow you type in a friend's name so you add them to your list.
An alternate way to invite friends on the PC and one that is much simpler is to launch Apex Legends and click the button that allows you to link your Steam friend's list with your account. As Steam is the biggest launcher on PC there is the liklihood many of your friends will be on that list.