Hello there, @Pattymulf. I'm here to share some details and will help you about your concern.
Let me answer your first question. If you're referring to sales per assigned customers, then yes, you can migrate. However if you're referring to Sales by Rep, it is only available in the QuickBooks Desktop version. If you want it in QuickBooks Online, you can utilize the custom fields and add Sales Rep in the column as a workaround. After that, pull up the Sales by Customer Detail report and filter Sales by Rep. Since this is just a text field, so you'll need to assign a sales rep every time you create an invoice or sales receipt.
Furthermore, about question number 2, Custom fields let you track the information that matters most to you and your customers. However, Classes represent a meaningful part of your company, like store departments or product lines. You can use them to get deeper insights into your sales, expenses, or profitability for each part of your business.
You can visit this following article to give you more insight about each feature:
Moreover, make sure you keep track of your books in QuickBooks Desktop and QuickBooks Online until you are sure QuickBooks Online is right for your business. Here's an article to that: What to do after you move from QuickBooks Desktop for Windows or Mac to QuickBooks Online.
Feel free to reach back if you have clarification or additional information with switching subscription to QuickBooks Online. Have a great day ahead!
