Change Catalog Headings & Text

You can modify the catalog output in Catalog Settings > Front-end labels. When you first navigate to this screen you will see all the available labels for individual product page:

Product Page Labels Edit

You can modify any of the labels and save changes. You will see immediate change on all product pages.

Product Listing Labels

If you want to edit labels on product listing please use the menu on the left and switch to listing pages labels:

Product Listing Labels