If you look carefully at an online slot machine or similar game, you will very likely see a button that says, ‘max bet’. This means maximum bet, which in turn is the maximum amount you can wager on a spin of the reels or a single bet on whatever game you are playing.
So, for example, a slot game with 20 lines might accept coins of between a cent and five dollars per line. It might also accept up to five coins per line. The max bet in this case would be $500. That would be too rich for many people, but it shows how the principle works.
A max bet button is usually provided to make it easier to place that bet if you want to. It means you don’t need to worry about clicking your way through the coin values and the bet levels for each line. While many players do not go for the maximum bet, some do, and having that button handy is a good way to make life easier for them. Of course, if you are going to bet on any casino game, make sure you can afford to lose the money you are about to wager.