If you’re accepted to your first choice university you should have accommodation sorted by now. But, if you’re going through clearing or don’t get the grades you need to get into your first choice university, applying for accommodation should be at the top of your to-do list. You should find an online application form for university accommodation on your university's website.
You might not have a choice, but think about where you'd ideally like to live and what your priorities are. A room on or close to campus could save you on transport costs and commuting time, but might be more expensive than a room slightly further away.
If your university doesn't offer its own accommodation, their housing office should be able to help you to find somewhere.