Good day, @jschmitt.
Thanks for reaching out to us. I'm here to help provide some insights about the Sales Order in QuickBooks Desktop.
There isn't another way to mark the Sales Order line item as closed. However, you can attach your Invoice to the Sales Order. This way you'll no longer need to go back into the Sales Order transaction instead, it will show as Invoice in Full (attached screenshot).
To create an invoice for a Sales order , you can check this article for the detailed steps: Create an invoice in QuickBooks Desktop.
If you need further assistance from our live support, I encourage you to contact our QuickBooks Desktop Support Team. They have the tools to do a screen share so they can walk your through the process.
Here's how you can contact our phone support:
That should do it! Please know that I'm just a post away if you have any other questions about the Sales Order. Wishing you and your business continued success.