When do you use 'on'?

'On' is usually used in informal situations to mean 'we'. Instead of saying 'nous allons aller au cinéma' you might say 'on va aller au cinéma'. It's very common to hear and see French people using 'on' instead of 'nous' when they're talking to their friends or family. 'Nous' is usually used when writing, or in more formal situations. It's also used to mean 'one' or 'someone' E.g 'On pourrait dire qu'il est stupide, mais je pense qu'il est intelligent' - 'One could say that he is stupid, but I think he's clever'