You can have up to five Lives at a time. If you lose a level then you’ll lose a Life. If you run out of Lives, you can’t start a level. However, Lives refill over time or you can use Coins to refill your Lives instantly.
You may also receive additional lives as rewards or when purchasing a Bundle. Additional lives that do not fit in your current Lives balance will be stored in your Inbox, from which they can later be claimed.