Discount for a customer advance payment without invoice

Thanks for joining us here in the Community, @Arzini.

You can record the advance payment as a retainer deposit and apply the discount to the next invoice. This is the best way to record the amount that you received in QuickBooks Desktop.

Before doing so, you need to create a current liability account for the deposits. This is because upfront deposits and retainers are liabilities, not income, even though you deposit the money into your bank account.

To create a liability account:

1. From the Lists menu, select Chart of Accounts.
2. In the Chart of Accounts window, right-click and hit on New from the pop-up menu.
3. Press Other Current Liability as to the account Type.
4. Enter a name for the account (for example, Upfront Deposit) in the Name field.existing upfront deposits or retainers.
5. Tick on Ok.

Once the account is created, you need to create an item to use when recording upfront deposits or retainers. Please see this link for complete details: Manage upfront deposits or retainers.

After that, when processing an invoice for the customer, enter the discount as a negative figure so it will be deducted from the original amount.

I'm also including here some resources about recording customers payments in QBDT for your reference: 

• Resolve common issues when applying a payment towards an invoice
• Create an invoice in QuickBooks Desktop

I'm just a reply away if there's anything else that I can help you with. Wishing you and your business continued success!