Are posts and pages part of the theme or in the database?

So I have 3 pages I am in the process of setting up now that I need to add to 60 other WP sites that all use the same theme with the only difference being the header?

If I add the pages to one theme and than download the corrected theme delete the header and upload it to another WP site does it copy the pages or no?

If not is there an easy way to copy pages from one WP build to another without manually making the pages?​