Most places in the US are in addition to the bill, it’s just that many people who don’t carry cash, so you can add it to your debit/credit on a separate line, but leaving cash is always an option. Some places that deal with a lot of non-tippers have mandatory gratuity or make it mandatory for groups above a certain size. Either way, I think it’s bullshit that the employees’ wages are not accounted for in menu pricing, and I’m expected to figure it out.