Thank you for responding. I am trying to duplicate a customized template because my client wants to incorporate a message in the body of the second template. My client intends to use the original template for one of his clients and the second template with message for all the other clients. So I downloaded this original template, convert it to Word, put the message (and chevrons on those data that can be changed such as date, description, amount, etc.), then import it to QBO. I did what you suggested below, i.e., I did not add nor delete any rows but still, my problem was not resolved. 

There are two lines in my original invoice template:

Description of product                             123.00

Description of service                               456.00

I mapped both lines to "Item, Product, or Service description" and "Amount/Line Total" since these are the only ones available in QBO. When I preview the invoice, both lines become "Description of product" and "123.00". I would really appreciate your help in this. Thank you.