If you’re in the UK, then Companies House is the place to start.

If you search google for “Company formation” then you should get a bunch of ads which will sell you off the shelf companies or guides to doing it with all the appropriate forms. It’s very straightforward (in the UK at least), and most lawyers just use a company formation agent anyway, so going direct will still be cheaper. They can keep you on the right track as well if you haven’t been through the process before.

Good luck!