Let me guide you on how to add different tags to each of the items on a single Invoice for one customer in QuickBooks Online.
Go to the Plus icon on the left side, then choose Invoice.
Select a Name in the drop-down arrow.
Enter all the transactions for that customer.
In the Tags section, select all the appropriate tags. Make sure each tag has a different group. So you're able to apply it. If you don't have yet, you can create a group with a tag.
Hit Save and close.
You can also write a word in the Message on statement box to easily locate the invoice.
After that, let's access your Transaction List by Tag Group to review the transactions. You can customize it to show the specific details. Let me guide you how:
Go to the Reports tab on the left pane.
Type Transaction List by Customer tag Group in the search box.
Click the Customize button.
Choose a Report period in the drop-down.
In the Row/Columns, pick Transaction Type.
Under Columns drop-down, choose the group name.
Tap Run Report.
You can also hit the Save Customization to save the report. It will save on the Custom report page. Memorizing reports in QuickBooks, it’ll help you save time since it automatically updates every time there are newly added transactions.