Make sure you're creating a new event or editing an existing one
Click Show Settings on the relevant ticket to reveal the advanced settings
Select a VAT rate from the VAT dropdown
You can choose to make the VAT inclusive in the ticket price but the default is the VAT will be displayed as an additional amount
You’ll need to add your VAT information in order to charge VAT on your tickets. Please see the section How do I add my VAT details? for more information.