Hi,

You can invite friends to start playing Bubbles IQ with you by pressing the Invite button at the bottom of the Weekly and Ranking stats lists or by pressing the Share button in your playercard. Players who have not played the game before and download the game through your invitation should be added as your friend in the game automatically. 
NOTE. In orderd for you to have your friend in your friend list you still need to add your friend manually by pressing the add friend button and writing in their friend code.