Is it possible to add an amount given by a customer and change given to customers in the sales receipt?

I can share some tips in handling that transaction, @higlopaints-mweb.

In QuickBooks Online, you'll have the option to record an advance payment as retainer or deposit. I'll show you how. 

First, you need to create a liability account to track the amount of the retainers you receive from your customers.

1. Select Settings ⚙, then select Chart of accounts.
2. Choose New.
3. From the Account Type ▼ dropdown menu, select Current liabilities.
4. From the Detail Type ▼ dropdown menu, Client Trust Accounts - Liabilities.
5. Enter a Name for the account (for example, Trust Liabilities) or accept the suggested name.
6. Click a Default Tax Code, enter an Unpaid balance, and an as of date.
7. Tap Save and Close.

Next, create a retainer item.

1. Select Settings ⚙, then select Products and services.
2. Click New.
3. From the Product/Service information panel, select Service.
4. Enter a name for the new product or service item (for example, Retainer).
5. From the Income account ▼ dropdown menu, select the liability account created in Step 1.
6. Tap Save and close.

Once you have set up the accounts and the retainer or deposit item, you can begin to create Sales receipts for the deposits or retainers you receive. You can follow these steps below: 

1. Select + New.
2. Click Sales receipt.
3. Choose the Customer name from the dropdown.
4. From the Deposit to ▼ dropdown menu, select the separate trust liability bank account you created, your main operating account, or the account this money will be kept in.
5. In the Product/Service column, select the Retainer or Deposit item you set up.
6. Enter the amount received for the retainer or deposit in the Rate or Amount column.
7. Tap Save and close.

If you prefer to invoice customers for deposits or retainers instead of receiving them directly. Here's how:

1. Select + New.
2. Choose Invoice.
3. Select the Customer name from the dropdown list.
4. In the Product/Service column, select the Retainer or Deposit item you set up.
5. Enter the amount received for the retainer or deposit in the Rate or Amount column.
6. Click Save and close.

To learn more about the process, you can check out this article: Record a retainer or deposit

Feel free to visit our Banking page for more insights about managing your bank transactions.

I'd like to know how you get on after trying the steps, as I want to ensure this is resolved for you. Please reply to this post and I'll get back to you. Take care always.