Thanks for joining us here in the Community.
I've got some insights to share about adding VAT into your quote in QuickBooks Desktop.
At this time, being able to add VAT to the quote isn't available. This option can only be added to an invoice since this is going to be a valid sales transaction.
For now, you can manually enter the VAT details on the description or memo field on the quote to indicate the VAT used in the said transaction.
I can see the convenience of having the option to enter VAT on quotes. Know that our developers are always gathering and considering new features to be added in the program to cope with our customers' needs.
To stay in the loop about our latest news and product road-maps, I encourage you to visit our Firm of the Future site regularly.
Lastly here are some references that you can check out about customizing sales templates in QBDT and on how to fix its issues:
You can always visit me here if you have any other concerns. I'd be glad to help. Have a lovely day!