Hi Can you guide me how to adjust customer advance agaisnt sale invoice

Hello there, rushikesh-s. 

Welcome to the Community forum. I can see it's your first time to post your concern here.

Adjusting the customer prepayment on the invoice is quite easy. We only need to open prepayment transaction and adjust the amount on it. It's a way to off-set the balance or record another amount on the invoice.

Let me walk you through on how to do it. Here's how:

1. Let's Go to Sales on the left panel.
2. In the Customers tab, locate the name of the customer whom transaction you want to adjust.
3. Click the payment and change the amount on it.
4. Let's make sure that the invoice is checked next to the Description column.
5. Click the  Save and New button at the bottom part of the page.
6. A  message will appear The transaction you are editing is linked to others. Are you sure you want to modify it?.
7. Hit Yes to confirm.

We can then go back to your customer's transaction list to review and double-check the status of this transactions. Here's a sample screenshot:

Aside from that, you can check out more details on how to record customer prepayments for the items in QuickBooks Online through this article.

I'm always here anytime you need more help. Just let me know by adding a new post below. Stay safe and be well!