Hi there honorine-muhriwa,
As the balance of all bills will have an effect on an Accounts payable account, Accounts payable is not an eligible account to be chosen in the line items of a bill. I can see how you'd like to be able to use this account for the purpose of entering bills. I recommend leaving feedback in the system by clicking on the Gear icon, then Feedback. The Comments made in that section are taken into consideration by our developers when designing new features for QuickBooks Online.
If you have any other questions, feel free to reach out here.
