I've some tips on how to add a customized column in your invoice layout, Gladys.
Before we start, could you please clarify if the Number of Boxes per SKU refers to the quantity of products? If so, we can change the column names during the customization.
Here's how:
- Go to the Invoice section of your dashboard.
- Click on Customize at the bottom centre.
- Choose either New Style or Edit Current.
- Click on the Content section.
- In the middle part of the Invoice template, rename the label Quantity to Number of Boxes.
- Click Done to save your changes.
Once finished, ensure to select your customized invoice layout in the Customize tab to apply the changes.

It's also worth noting that while you can rename the Quantity label, adding a separate column just for the Number of Boxes for each SKU is not possible. As a workaround, you can use the Description field to indicate the number of boxes for each SKU.
As a workaround, you can use the Description field to note the number of boxes for each SKU.
I also recommend submitting feedback to our Product Engineer. Your suggestions will be considered in the next software update, depending on how many users have the same request.
Here's an article in case you want to use reports to track your cash flow to view current and future finances in QuickBooks Online (QBO): Track cash flow in QBO.
Feel free to reply to this post if you need further assistance.