Hi kmerrill72,
The option to select which item the payment goes isn't available in QuickBooks.
For example, if you have an advance payment, it will be divided into all the items. However, you can create a separate invoice per item. This way, you'll have the option to associate the payment to the correct item.
In case you want the invoice to be paid online, you can add a Pay Now button. Here's an article for the detailed steps of this option: Let your customers pay invoices online.
Also, if you have customers that you invoice regularly, you can create a recurring invoice.
If there's anything that I can help, please tag my name. I'm here to help you out!
