Can I itemize an invoice? Can client pay deposit amount from invoice and not total due?

Thanks for checking this with us, @stewartaerialpho,

Yes, you may apply the deposit as a partial payment to a customers invoice. All you need to do is adjust the amount when receiving them in QuickBooks.

Here's how:

1. Click the + New icon then Receive Payment.
2. Fill in the customer name and mark the invoice to be paid under Outstanding Transactions.
3. On the Payment column, enter the deposit amount (see screenshot).
   
4. Click Save and close.

Also, if this you are sending online invoices, the customer can change the amount on the payment page. See this: 

For tips about QuickBooks sales and invoicing, please see this link: Sales and customers in QBO.

Let me know if you need anything else. I'll be around for help at any time. Have a good day!