This guide will tell you how to enable Crossplay in Apex Legends & Invite or ADD Players.
1- First of all, you have to boot up your game, then go to options, and click on Settings. After that, select the gameplay from the top of the screen and scroll down until you find the cross-platform play. You need to make sure that it is enabled.
If this option is disabled, then your friend from other platforms will not be able to play with you and also it will affect your matchmaking time. It is because a very small number of players play by turning on their crossplay.
2- After this, go to your friend list, and click on Find Friend on the left bottom of your screen. A small search bar will open, where you have to type the name of your friend and then you click on the Search button. It will show you the result that shows you the people with the same name. If you want to send a request, then take your cursor to the name of that person, and then press X on it.
3- When this player will come online, you will find him under your friend list. You have to go to their name and press X to invite them.