How do I include an advance on an invoice

You're in the right place, @josephmaxmiller. I have all the instructions you'll need in recording a deposit from customers and how to receive invoice payments against it.

A retainer or deposit is an advance payment from customers before providing any products or services. It's treated as a liability since it doesn't belong to you until it's used to pay for services. When you invoice the customer and receive payment against it, you'll turn that liability into income.

First, let's create a liability account to track the amount of deposit you receive from your customers.

1. Go to the Gear icon, then select Chart of Accounts.
2. Click New.
3. From the Account Type drop-down menu, select Other Current Liabilities.
4. From the Detail Type drop-down menu, Client Trust Accounts - Liabilities.
5. Enter a name for the account (ex. Trust Liabilities) or accept the suggested name.
6. Select an option from the When do you want to start tracking your finances from this account in QuickBooks? dropdown list.
7. Select Save and close.
   

Then, let's create a retainer item.

1. Go to the Gear icon, then select Products and Services.
2. Select New.
3. From the Product/Service information panel, select Service.
4. Enter a name for the new product or service item (ex. Retainer).
5. From the Income account ▼ drop-down menu, select Trust Liability Account.
6. Select Save and close.
   

Next, you may create a trust liability bank account. If you keep the money in your operating account, you don't need to follow this procedure.

1. Go to the Gear icon, then select Chart of Accounts.
2. Select New.
3. From the Account Type ▼ drop-down menu, select Other Current liabilities.
4. From the Detail Type ▼ drop-down menu, select Trust Accounts- Liabilities.
5. Enter a Name for the account (ex. Trust Liability Bank Account) or accept the suggested name.
6. Select an option from the When do you want to start tracking your finances from this account in QuickBooks? dropdown list.
7. Select a Default Tax Code and enter an Unpaid balance and as of date.
8. Select Save and close.

After that, you can begin creating a sales receipt or invoice for the deposits or retainers you receive. For the detailed steps, refer to this article and proceed to Step 4: Record a retainer or deposit.

Lastly, when it's time to charge your client for their purchases, you can turn retainers into credits on invoices. This decreases the amount in your liability account and applies the credit to your customer's invoice, turning it into income. Follow the same article above and continue to Step 5 for the detailed instructions.

Moreover, you can make recurring transactions in QuickBooks should you have customers you invoice regularly. You can refer to this article for more info: How to create a recurring invoice and manage recurring transactions.

I'm always here if you need any more help in handling a retainer in QBO. Have a wonderful day!