Your company details
Your company name and registration number — the eight-character number issued by Companies House.
The accounting period your return covers, which is usually your company’s financial year.
Your Corporation Tax UTR
Your UTR (Unique Taxpayer Reference) is a 10-digit number HMRC uses to identify your company for Corporation Tax.
You will find it on letters from HMRC about Corporation Tax, or in your company’s HMRC online account. Note that it is different from your personal UTR.
Your Government Gateway login
This is the user ID and password you use to sign in to HMRC online services for the company. OneFiler uses it to submit your return, and never stores it in plain text.
If you have never set one up, you can create one through HMRC — you will need it to file at all, whichever software you use.
Your figures
Your year-end figures — income, expenses and the balance sheet position.
If your bookkeeping is in QuickBooks or Xero, you can import these directly rather than entering them manually.