VAT-registered companies are required to enter tax rates when creating an invoice, thecleanhomeedit. This is to ensure compliance with tax regulations and accurately calculate the VAT owed.
If the transaction is not VAT-eligible, you can select No VAT (0%) from the VAT column on the invoice. Otherwise, you can choose the applicable rates from the selection. I've included a snapshot below for your reference:

You can also set this as the default option to stop VAT from appearing in future transactions.
Next, please consider reviewing this article to learn how to record payments once your customers have paid their invoices: Record invoice payments in QuickBooks.
If you need additional assistance managing your sales transactions, please don't hesitate to let us know.