Hello there, @SHarrisFinancial,

I'd be glad to provide you the steps on how to write a refund check in QuickBooks Online.

You'll first need to create a bank deposit using the Accounts Payable so you can link the vendor credit to the deposit.

Here's how:

1. Click the Plus (+) icon.
2. Under Other, select Bank Deposit.
3. Select the Bank Account where you want to deposit the funds.
4. Scroll down and go to the Add funds to this deposit section.
5. Select the name of the vendor in the Received from column.
6. Pick Accounts Payable in the Account field.
7. Enter other details in this table.
   
8. Click Save and close.

Then, link the deposit with the vendor credit.

1. Click the Plus (+) icon.
2. Select Check under Vendors.
3. Select the vendor from the Payee drop-down list.
4. Add the Deposit and Unapplied Payment that appears on the left side in the Check page.
5. Click Print check to print it.
   
6. Then, Save and close.

For your guidance with the solution above, you can go through this article: Manage vendor credits.

To learn more about printing checks, please check this out: How to print checks.

If you need assistance with this, just leave a comment below. I'd be glad to lend a hand.