Yes, although it always depends on where you want to play from. Depending on the legal situation there are differences. At least with iOS where you are dependent on the Apple Store. With Android it looks different and the legal situation is uninteresting. It is important to choose a real casino as an app and not an app where you exchange real money for play money. This way of playing is legal almost everywhere - even in the USA - but in principle you only pay to play and not to collect real money winnings. Good real money casino apps are for example from LeoVegas or 888.