If VAT/GST pricing feature is enabled in Event Details, you can configure the VAT/GST percentage for registration prices. 
  1. Log in to ACTIVE Works with Existing ACTIVE Passport Account
  2. Select desired event
  3. Click Setup tab
  4. Click Registration categories
  5. Under desired category, click Add a price
  6. (Optional) Click Edit beside the target existing price type
  7. Enter Price type name and Display name
  8. Enter Price (incl. VAT/GST) and VAT/GST amount (percentage)
AUI
  1. Make other necessary selection
  2. Click Save