1.Tick the VAT registered box in the Company Properties dialog (Set Up > VAT):

•Only tick the VAT Cash Accounting box if you use HMRC's VAT cash accounting scheme. (Note: If using VT Cash Book, this setting does not have any effect, as you can only enter payments and receipts in VT Cash Book, therefore VAT will be accounted for under cash accounting regardless).
•Only tick the Business is situated in Northern Ireland or the EU box if your business is in Northern Ireland or the EU, and trades with other EU countries. (Note: If using VT Cash Book, this setting does not have any effect, as intra-EU transactions cannot be entered in VT Cash Book).
2.Enter your 9 digit VAT registration number and click OK.