You can add in-game friends either by connecting to Facebook for your Facebook Friends or by using a Friend Code.
This feature can be found by going to the Settings > My Friends
To get your Friend Code, open the tab with an 'i' on it and then tap on 'Get your code!'.
This code will allow other people to add you as a friend if you give it to them.
If you know someone’s Friend Code you can add them on the tab with a '+' on it.
The other tabs will allow you to remove friends and see your friend requests.
Adding more friends will allow you to send and receive more gifts!
Pro tip! By tapping on another player's Player Card from the Leaderboards, you may also see the option to add them as a friend! If it doesn't show, this means that they have disabled their friend code. You can do the same in the Friends menu.