Every limited company that is based in the UK is subject to corporation tax on their profits. Limited companies that are non-UK based can still be expected to pay corporation tax.
You must first register your company with HM Revenue and Customs (HMRC), using its official forms, so it knows you are liable for corporation tax.
If your company is liable for corporation tax, you must calculate your company's profit for each accounting period and how much corporation tax is payable on those profits.