You can add friends on 3 ways from the Social Menu(FindFriends tab):
  1. In Find Friends tab, there is a list of suggested players. You can invite them by tapping "Invite" button. The list refreshes every 8 hours.
  2. You can also invite players if you know their Nanobit ID. It is located in the Find Friends tab. To add a friend, just type players username and tap "Invite".
  3. After connecting to Facebook, all your Facebook friends who play My City and are also connected will be automatically added as your friends. You can find them in Friends tab.
Social Menu is available from level 7.