Once you've activated the Vat reporting option from your Company settings, you can then mark your invoices for VAT.
Add invoices to a VAT period
Access the Inbox or Archive tab within the Sales or Purchases folders.
Use the checkbox to the left to select your invoices.
📌TIP: Use the master checkbox top left to select all the invoices. Use the date and status filter to narrow down the list.
Once you've selected the invoices, click Actions and select Tag from the dropdown menu.
A pop-up window appears to select both the year and VAT period required.
Click Apply.
Next step
After you've marked your invoices for VAT, you can then filter your tagged invoices before you export them.