how to set up product listing to have permanent items in the listing

[psco]

Hello,

I have products which I want to add some items lines to and for them to show in the front end with what I input from the back end. I am confused as what to be looking for here, is it how to add form fields, meta tags, I was thinking it is in the template?  

My purpose for this is I sell on 3 marketplace. each has there own listing requirement, So I was thinking I could add them into the shopify and then they would upload to market place and save me time from going back and forth.

Thanking you in advance.

Ron