They would store them on the game until you removed them to a wallet. You can use mobile BTC wallets (coinomi, JAXX) or move them to a paper wallet. You can make one of those here. https://www.bitaddress.org/bitaddress.org-v3.3.0-SHA256-dec17c07685e1870960903d8f58090475b25af946fe95a734f88408cef4aa194.html Let me know if you have any other questions and I'll try to help.