A government issued ID such as a driver’s license, a passport, or a state ID is ideal. If you’re a foreigner and you have only foreign IDs, they should work provided that they are government-issued and they have all the necessary information, particularly your age. Your passport should work best though. There have been cases of foreign licenses being turned down in some casinos, so it’s still best to have your passport handy.
Before playing in a casino, make sure that you have a proper ID. This is because you won’t only need an ID for age verification; you will also need it to claim your winnings. If you cannot produce a valid ID, the casino might refuse to release your money.