can i edit an invoice with VAT after saving?

I'm happy to inform you that yes, you can edit an invoice with VAT even after saving it, jeffrey20.

The error message occurs due to momentary delays in the system's processing. I recommend giving it some time, and the tax calculation should be completed shortly. Or you can refresh the page to fix it.

I'm sharing an article for a step-by-step process to personalize your sales forms in the future: Customise invoices, estimates, and sales receipts in QuickBooks Online.

In addition, you can also consider creating and sending your customers statements that give a clear overview of their invoices, payments, credit memos, and balances.

If you have any more questions or need additional help, please feel free to ask, jeffrey20. I would be more than happy to assist you further.