I've recently changed from QB Desktop Pro 2019 to QB Online. Having trouble adding a field for Sales Rep on Income by Costumer Summary Report. No option for the field.

Hi @huntsvilleevent1,

I'll take care of your concern about tracking your sales transactions with a sales rep on the form in QuickBooks Online (QBO). 

The custom fields in QBO allows you to include additional details in your forms. These can either be visible to the customer when you send out the form or not. The system, however, doesn't track whatever info is in these custom fields. 

A workaround I can provide is for you to utilize either class or location tracking in your QBO company. Say, for example, you decide to use the location tracking feature. Follow these steps to enable this feature:

1. Go to the Gear icon.
2. Select Account and Settings.
3. Click the Advanced tab.
4. Press the Categories section.
5. Check Track locations. 
6. Hit Save, then Done.

To continue, see this article: Customize sales forms by location. Look for the Add location section, and go from there.

On the other hand, if you decide to use class tracking, check out this article: Track your transactions by class. 

On the same note of customization, open this article: Customize invoices, estimates, and sales receipts in QuickBooks Online. It's a detailed guide on how you can customize your sales forms in QBO, along with a short video as a reference.

If you have other concerns with customization in QBO, then post a comment below. I'll be around to help you out.