Welcome to the Community, Manizha1983. 

There may be transactions associated with your customers as an expense billable to a customer. This shows the bills in the Profit and Loss report. Just check the bills if they are billable or not by clicking the bill transaction itself. If these bills are not billable, we can delete the customer's name in the Customer:Job column.

Also, bills will use income accounts when using items that are purchasing items that have only one account (an income account). To resolve this one, follow the steps provided by BigRedConsulting on this thread. Then, try running the report again to see if sales are showing both bills and invoices.

If the same thing happens, there may be damaged data on the company file you've been working with. We can run the Rebuild Data tool is built-in to fix any company file data issues. Just follow the steps and detail in this article: Fix data damage on your QuickBooks Desktop company file article. We can also repair your QuickBooks Desktop to fix any damaged components in the software.

Feel free to visit our Reports page for more insights about managing your reports in QuickBooks. 

Please let us know after performing the steps provided, as I want to ensure this is resolved for you. Just reply to this post and I'll get back to you. You have a good one.