HM Revenue & Customs sends all newly formed companies a pack of forms. Return the relevant forms ASAP.
Provide the legally required information on all company communications, including on e-mails and websites.
Active companies are obliged to file their accounts with HMRC and Companies House.
If your company is dormant it may be able to file a simplified set of accounts with Companies House.
Does your company hold information on individuals? If so you may have to make a notification.
Register as a New Employer with HMRC. Supply all employees with a written contract or statement of the main terms of their employment.