Payment link to Sales orders.

Welcome to the Community, @PDPTPLEX.

I've got you covered, and let's work this out so you can connect the payment received via payment link to a Sales order in QuickBooks Desktop (QBDT).

To collect payment in advance, you can use a payment link. Whenever a customer pays using the payment link, it automatically generates a sales receipt. However, the best way to apply the credit is by converting the sales order to an invoice. Once you issue the invoice, you can apply the credit to reduce the total amount due. Please note that payments made through the link will show as credits for the customer, and customers can't change the amount or pay partially. After submitting payment, a receipt is automatically generated.

When you're ready, here’s how you create the payment link:

1. Go to the Customers menu.
2. Choose Payment Links.
3. Enter the amount and description. 
4. Select an existing customer or add a new customer.
5. Enter the customer's email.
6. Set the appropriate payment method (credit card or ACH).
7. Click Send Payment Link.

QuickBooks will then send an email to your customer containing the payment details and a Pay button. You will also receive a confirmation email. Additionally, you can copy the auto-generated link and share it via your preferred messaging channel. To learn more about how this feature works, you can visit this page: Payment Links for QuickBooks Desktop. 

You can also check this article that will help you in managing customer payments for online invoices and in-person sales: Receive and process payments in QBDT.

I'm only a comment away if you have any questions throughout the process of the Payment link in QuickBooks Desktop, PDPTPLEX. Take care and enjoy your weekend!