How do I apply a down payment, which was made without an invoice, to a Project so that it appears as income in the project?

Thanks for posting to the Community, @appletreeconstru.

You can create a sales receipt when you're paid on the spot (status is automatically marked as paid) or by creating an invoice to make it appear as income in the project.

Let me show you how to apply for the down payment by using sales receipt:

1. Go to + New and then select Make a sale.
   
2. Select the project on the Customer's field.
3. Enter the amount and product/service.
4. Click Save and close.

Here's how to apply for the down payment in an invoice:

1. Go to + New and then select Send invoice.
2. Select the project on the Customer's field.
3. Enter the amount and product/service.
4. Click Save and close.

Or by going to Projects and then select the project that you've created:

1. Click Add to project on the upper right, select Invoice.
   
2. Enter the product/service and amount.
3. Click Save and Close.

You can refer to this video: How to Use QuickBooks Projects to Track Project Income & Costs.

If you want to receive deposits from customers before performing any services, you can check this article: Record a retainer or deposit.

You can always leave a message through this post if you need further assistance. I'll be arount to help. Enjoy your day!