It depends how you want to track your expenses. It could be done as a cheque directly from your bank account. But for reporting purposes and being able to track all transactions for the vendor easily, if I were you I would be entering their invoice as a bill. As soon as you know the supplier has taken the money out of your bank, use 'Pay Bills' to pay that vendor's invoice. That transaction will debit your bank account and credit your A/P liability to that vendor. That is if you don't have your bank account connected to QBO. If you do, I'm not sure how the bank dumps the transactions into QBO, as I have never allowed the bank access to my QB. In my opinion, it is messay and complicated when dumping transactions automatically into QB. I maintain much more control by entering and paying bills myself. Whatever your preference, I guess.
