You can register online via the government website. You’ll need your government gateway details to log in to access the VAT registration form. Alternatively, you can also register via post with one of the following forms:
VAT1A if you’re an EU business ‘distance selling’ to Northern Ireland
VAT1B if you import (‘acquire’) goods into Northern Ireland worth more than £85,000 from an EU country
VAT1C if you’re disposing of assets on which 8th or 13th Directive refunds have been claimed
Post your completed form to:
HM Revenue and Customs
Further guidance can be found on the government website.
Also, check out our more detailed blog post on this topic.