Hi there 
Ghost as a platform allows you to publish content and run a paid publication - but in terms of payments it integrates with external payment gateways. Detailed customer information that you’d need for VAT purposes is never passed into the Ghost dashboard.
If you’re using the Stripe integration there are lots of accounting tools that integrate directly with Stripe for this exact purpose. I’d recommend contacting their support team for further information about that 
You may already know this, but some publishers who are creating email newsletters and digital publications have found they are exempt from VAT. Here’s some further reading for the UK, for example. If you haven’t already, we always advise speaking with a professional accountant about how VAT applies to your individual circumstances.