Importing IIF for Payments and Invoices, Linking, marking PAID?

You may need a 3rd party app to do so.

Do you know of any 3rd party apps that does that?

You may keep using IIF data to be imported into QBD. But you have to use a 3rd party tool to import Receive Payment data in XLS/CSV into your QBD. 

https:// transactionpro.grsm.io/qbd

https:// partners.saasant.com/affiliate/idevaffiliate.php?id=5051_2

The template should be like this

@Carsco 

RE: Question is if there is a way to IIF import the payments and Invoices in already linked and marked PAID?

There is not.  QB will not link payments to invoices as you import them.  Intuit could change this at any time, but they have not.

If I import invoices and then payments into QB (I'm using Mac Desktop), how do I then apply credit memos and payments against the outstanding invoice(s)?

Thanks for joining this thread, Reconciler.

You can apply credit memos and payments to invoices through your Receive Payment screen.

Here's how:

1. In the top menu bar, go to Customers.
2. Choose Receive Payment.
3. From your Received From drop-down list, pick the customer's name.
4. If you need to apply credits to an invoice, tick your Apply Existing Credits? checkbox. To apply existing payments, enter the payment details and select the appropriate invoice(s) to apply them to.
5. Click Save.

You'll also be able to find many detailed resources about using QuickBooks in our help article archives.

Please don't hesitate to send a reply if there's any additional questions. Have a great day!