Hello there, denisemc.
The amount on the supplier invoice depend on your supplier whether they'll include the VAT or not. If they didn't include it, you'll have to record it manually. With that said, you might have to consult the supplier about the VAT amount. Then, reach out to your accountant on how to record it. You're likely to create a journal entry with this.
Note that QuickBooks only calculates the VAT on the customer invoices and other sales transactions.
Let us know if you need anything else. Additional details would be much appreciated.