When creating a new QB file for the new year, how do you handle payments for previous years invoices?

My accountant does not like me receiving payments unless they are associated with an invoice.

If you are on cash basis, you should use Sales Receipt, not Invoice.

https://quickbooks.intuit.com/learn-support/en-us/help-article/sales-receipts/create-sales-receipts/L1sqnN6MJ_US_en_US

Hello, @davidmatyas. It's great to know that you're in the process of creating a new QuickBooks Desktop file. I'd be delighted to assist you by guiding you through the steps to manage your previous invoices, and ensuring your transactions are accurately recorded in your account.

Since you're using a cash basis, I will agree with Fiat Lux - ASIA on creating a Sales receipt. A cash basis is a bookkeeping method in which you regard income or expenses as occurring at the time you receive a payment or pay a bill.

In your case, you can generate a sales receipt in your new company file to record payments received at the time of the sale. Sales receipts can account for payments made by cash, check, or credit card. To create a sales receipt, please follow the steps outlined below:

1. Go to the Customers menu.
2. Choose Create Sales Receipts/Enter Sales Receipts.
3. From the Customer: Job drop-down, select a customer or job.
4. In the Memo column, you can enter a message indicating invoice payment.
5. Fill in the necessary information.
6. Click Save & Close.
   

 For detailed information on creating sales receipt, see this article: Create sales receipts. 

After sharing the following steps, I would still recommend consulting with your accountant. They can guide you on how to accurately record the invoices to maintain the accuracy of your financial data.

Once you've recorded everything in your new company file, I'll include this article that explains various methods for tracking customer transactions in QuickBooks Desktop: Get started with customer transaction workflows in QuickBooks Desktop.

If you have any other questions about managing previous invoices or any concerns related to QuickBooks Desktop, please don't hesitate to leave a comment. I'm here to assist you. Have a good day.