Can I correct a bill from 2020 without impacting prior year balances? I would like to make this bill a zero balance but don't want to change my A/P balance from 2020.

Yes, we can zero out your bill by creating and linking a vendor credit dated this year 2025, tbunce. So, this will also not affect your A/P balances for 2020. I'll provide a step by step guide for your complete guidance.

To modify a vendor bill, go to the expenses tab, choose vendors, find the bill you need to adjust, and apply for a vendor credit. Please note that when adding a vendor credit it should be dated today in 2025, so that the AP account for 2020 will not be changed. 

Also, this will impact to your quantity of the item returned. If you don't want to affect your quantity since it was already 2020, I'd suggest creating a journal entry and ensuring that it is also dated for 2025. I'd suggest to consult an accountant for comprehensive guidance regarding the accounts that will be impacted.

Now, let's create a vendor credit to zero out the balance:

1. In the upper left corner, click on + New.

2. Under Vendors, select Vendor credit.

3. In the drop-down menu for Vendor, select the appropriate vendor.

4. Under Item details provide information under Product/Service.

5. Enter a description and the specific amount in the Amount field.

6. Click Save and close.

We can run an A/P Aging Detail report and assure to set it to a specific report date.

Here's how:

1. On the left navigation bar, click on Reports.
2. In the search box labeled, type Accounts Payable Aging Detail.
3. The report will display the details of your accounts payable balances, organized by age categories.

We can check out this article for your reference: Enter vendor credits and refunds in QuickBooks Online.

 
For future reference on how to run a financial reports in QBO, check out this article: Run a report in QuickBooks Online.

Before we wrap up, I suggest you explore QuickBooks Live Bookkeeping to streamline your accounting, maintain precise financial records, and access professional support. This could free up valuable time, allowing you to concentrate on expanding your business.

Correcting a bill without impacting the balance in QuickBooks Online (QBO) is crucial for accurate financial records. If you need further assistance, leave a message here for prompt assistance. Have a great one.