Hi theshoulderoakth,
If you don't do invoices, I can think that you're using sales receipts. It has a VAT field (see screenshot) where you can choose the right code for your sales transactions.
On the other hand, we're unable to do tax advice here. I'd recommend reaching out to your accountant if you have a question on VAT codes. You can also use this article as an additional reference: Common VAT Codes.
Please go back to this thread if you have other questions.