Can indicate Sales person ref on every invoice created?

I'm here to help and provide some options for tracking a salesperson on an invoice in QuickBooks Online (QBO), Wendy.

We can use the custom fields to add the salesperson's name to your invoices. Then, manually enter their name in the custom field whenever creating the transaction. Here's how: 

1. Go to the Gear icon on the top menu.
2. Select Custom fields.
3. Click Add field. If this is your first time creating a custom field, choose Add custom field.
4. Enter a name in the Name field.
5. Select the All Sales forms or Purchase Order checkbox. Or, select both.
6. To show the custom field on printed and delivered forms, turn on Print on the form. Otherwise, it’ll only appear in QuickBooks Online.
7. Press Save.

To learn more about adding custom fields to your sales forms and purchase orders, check out this article: Add custom fields to sales forms and purchase orders in QuickBooks Online.

Once done, run the Sales by Customer Detail Report, and filter Sales by Rep to show all invoices with an assigned salesperson. Let me guide you on how:

1. Go to Reports in the left pane.
2. Select Sales by Customer Detail in the search field. 
3. Fill in the correct date range
4. Click Customise.
5. In the Rows/Columns, put a checkmark on the Sales Rep box.
6. Expand the Filter section.
7. Put a checkmark on the Sales Rep box.
8. Press Run report.

You can check out this article to learn more about customizing your reports: Customise reports in QuickBooks Online.

The Community is always available if you need help with customising invoices or any QuickBooks-related. We will reply as soon as possible.