We have a car rental/lease business. Do we add the all the cars in products/services? The income account should be what? Inventory Asset or Sales How do we add the cost?

Hello, karanspoint-gmai. 

Thank you for reaching out to the Community. Your car rental/lease business is managed as Service items, or Non-inventory Items because that links to the Rental Income account.  

Here's an article you can read for more details in changing accounts for your Product and Service: The account for a product/service item.  

You might also want to check this article for reference in case you want to change your product and service item types. This will guide you through the steps by steps process: Change product and service item types in QuickBooks Online. 

Should you have any other concerns or questions in the future, you're always welcome to post here. Our door is always open to help. Take care and stay healthy!