Hi there, @JEM20. I'd be happy to assist you with recording the payment in QuickBooks Online (QBO).

You can record the payment using the actual date to keep the correct data entry. You can create a Sales receipt transaction and note the event in the Memo section for documentation purposes only. 

Here's how:

1. Click on the + New button and select Sales receipt.
2. Fill in the details on the form.
3. Enter the details on the Memo section of when the event occurred.
4. Select Save and close after reviewing the details on the form.

This is what it looks like:

Moreover, if you are trying to record a payment as a Non-profit organization, I'd recommend consulting with your accounting professional for the best advice on how to handle this transaction. Your accountant will know more information to provide based on your business needs. If you don't have an accountant, you can find one here in our Resource Center. 

Moreover, I've got a reference about recording a pledge: Track funds you receive from donors in QuickBooks Online. This also contains steps on how to record in-kind donations and how to track them effectively.

Please don't hesitate to let me know if you have any other questions or concerns. I'm always here to lend a hand. Take care!