You can access your friend list from the main menu. From here you can see all your friends and their characters, and invite them to play on the same team with you.
Playing with friends are made for playing only on team vs but there is also a glitch where the FreeForAll can be accessed.
You can also bring in more friends who do not have Respawnables with the "add new friends" button.
Once you're in multiplayer mode you can create your own squad from here by inviting a maximum of four friends to form a squad.
When you invite a friend into a squad, an alert notification will automatically be sent to their device.
If you're the squad creator, you'll see a silver crown symbol next to your name within the squad.
Once you're on the battlefield, you'll be able to recognize friends by their names, which will be green instead of blue.
Sometimes it can happed that your squad is divided on the two different sides, no worry, after the round your squad will be together again.
There was a glitch for iOS users where you are not able to send requests. This might not occur to everyone but this sometimes happens. After the Respawnables 3.0 Update, It was fixed and you were able to play with your friends again.