We're aware some players turn tiles upside down in in-person games as personal reminders. But we made a deliberate decision not to include that feature in I LOVE MAHJ. In our experience, it can become a crutch for players and, in in-person games, the orientation of tiles can unintentionally reveal information about a player's thinking or hand.
For those reasons, there isn't a way to flip or rotate tiles in your hand on our platform.