Does applying to university need you to declare a major? Or do you just need to declare a college in the university that you want to attend?

I’m confused right now since some forums where there are chance-me posts ( posts that people publish their stats and ECs so others can predict the probability whether or not they will be accepted) that include which major they are wanting to apply to but not colleges. My brother (who just graduated) said back when he applied, there was no need for declaring a major.