Payment made to vendor has been directly applied to his account, through categorization of bank payment, there after bank has also been reconciled. how to assign bills

Thanks for posting in the Community, Aamer. Let me give you the steps so we can record the bill.

We can create the check or expense to record the payment that has been directly applied to the vendor's account. 

Here's how: 

1. Create check or expense: 
   
   •Go to the +New icon.
   •Create a Check or Expense.
   •Select Save and close. 
   
   
    
2. Create Bill: 
   
   •Go to the +New icon.
   •Create a Bill. 
   •Make sure that it has the same category and amount as the Check or Expense created. 
   •Select Save and close. 
   
    
3. Edit the Check or Expense category.
   
   •On the left panel, click Expense, then select Vendors. 
   •Pick the vendor's name.
   •In the Check or Expense created, select the View/Edit dropdown. 
   •Under the Category, change it to Accounts Payable (A/P).
   •Click Save and close. 
   
   
    
4. Create Pay Bills. 
   •Go to the +New icon.
   •Create a Pay Bills.
   •This is to link them and mark the bill as paid.

After this, when the balance is zeroed out, we can ensure that the Check or Expense is linked to the Bill. 

Additionally, I've added this article for your reference and learn how to record a refund or credit from a vendor in QuickBooks Online: Enter vendor credits and refunds in QuickBooks Online.

Please don't hesitate to reply to this thread should you need additional assistance managing your bills in QuickBooks Online. I'll keep an eye out for it.