During play, you'll sometimes be awarded 🪙COINS.
Coins can be used to purchase various kinds of hints while playing a puzzle. Each puzzle offers one or more kinds of hint - please refer to the instructions for each puzzle for full details.
You can see how many coins you currently have in the status bar area at the top of the screen. You can tap the coin meter to go to the in-game Store where you can buy or earn additional coins.