@meesam, your post was moved to a new topic because it was unrelated to the one where you posted it. Please do not divert topics with unrelated questions. That makes it hard to get answers or help of any kind.
You don’t need a custom report to do what you want. You can use the built-in Sales Invoice Totals by Custom Field report after creating a custom field for your salespersons. Then drill down on a person and search for the customer’s name.