Click + New on the top left and then select Expense/Check.
Enter Check/Expense details like Payee, Bank Account, Payment date, Category details/Item details, and Amount.
Hit Save and close.
On the other hand, if you created a bill recently to report your Accounts Payable accurately, you'll want to use the Pay Bills for the online service you want to pay offline or electronically. Feel free to check this article for the instructions: Enter and manage bills and bill payments in QuickBooks Online.
Follow these steps to pay a bill:
Click + New and then select Pay Bills.
Check the vendor bill box you want to pay.
Click the Triangle button beside Schedule payments online.