how to use class

I want to add more content for this question as I could not add more with my original posting for some reason.  we classify by locations and each locations (NY, CA, FL)  has own bank account.  we want to run balance sheet and PL by location each month.    customer sometimes pay NY business invoice to CA bank account as customer wants to pay all invoice at once.  in that case do I need to enter CA on top and NY at the item line?  this gives me accurate PL and balance sheet?  PL - I want to show actual profit and loss for each location without balance sheet become unbalanced...your advice would be appreciated.

in desktop, the class selection at the top will report on the whole invoice, and if you select it first it will fill in the class for all items

class on an item line, reports on just that item

So if you several items on a transaction, each you want to report in a different class, use the line item classes only.  Because if you use the top class you will get all line items reported for that class