If you navigate to ‘Posts’, ‘Pages’ or ‘Products’ in your dashboard and click ‘Edit’ to edit a post/page/product, you will see the extra ‘Header Image’ section to the right of the main content area and below the ‘Page Attributes’ section (below ‘Tags’ in post editor and below ‘Product Tags’ in product editor).
Here you can upload an image to use as the header image for that page/post/product.
