You can send gifts to your friends and request gifts from them in the game.
To request a gift:
1) Tap on Social in the top right of the Main Menu.
2) In the Social section, tap on the “Gifts” button on the sidebar and tap on the “Request Gift” button to send a gift request to all of your friends. 
3) Congratz! You have sent a gift request to all of your friends. Now you need to wait for them to respond.
4) To send a gift to your friends, tap on the “Friends” button at to top of the sidebar. Select a friend to which you want to send a gift and tap on the “Send” button.
5) To collect gifts, tap on the “Gifts” button on the sidebar and tap on the "Collect" button. If you have multiple gifts, you can tap on the "Collect All" button and collect them all.