Thanks for coming back, @vconger-thehunle,

You can link a payment journal entry to an invoice. You will only need to change the payment date if you want it to be different from the time the invoice is created. 

Here's how:

1. Go to the + New icon and choose Receive Payment.
2. Enter the name of the customer.
3. You will see both journal entries under Outstanding Transactions and Credits (reversal).
4. Update the Payment date to when you received it.
   

I also have another approach that you might want to try. If there is no invoice yet, you may set up a retainer deposit for the payment, and apply it at a later time. Here are the steps to do that:

Step 1: Create a trust liability bank account: (optional)

1. Go to the Gear Icon then pick Chart of Accounts.
2. At the top of the screen, click New.
3. Use Bank Account for the Category Type.
4. Select Trust account under Detail Type.
5. Enter the name you want. Example: Trust Liability Bank Account, or leave the account name as is.

Step 2: Create a trust liability account:

1. Choose the Gear Icon then Chart of Accounts.
2. At the top, press New.
3. Select Other Current Liabilities under Catergory Type.
4. Use Trust Accounts – Liabilities under Detail Type.
5. Enter the name you want the hit Save.

Step 3: Create a product or service item that uses the trust liability account

1. Tap the Gear Icon then Products and Services.
2. Click the New button.
3. In the Name field, enter a description for the product or service item. Example: Retainer.
4. Click the Income Account drop-down and select a Trust Liability account.
5. Press Save.

To get more information about this and how to apply the retainer as payments, see this article: Record a retainer or deposit

If you have other questions about this, please let me know by tagging my ID. I'll be right here to help you anytime.