The Collection page holds all the products included in a particular collection.
Use the theme editor to show or hide the collection image and set the products per page for the collection pages. There are additional controls in the theme settings, as well.
Show collection image
To display the Collection image on your collection page, go to Customize > Open a collection in the right-side preview > In the left-side settings, open the Collection pages section and enable Show collection image
This will display at the top of the collection page, between the header and Utility bar.
Set the products per page
Control how many products are included per page by using the Products per page slider. Choose an option between 24 (minimum) and 48 (maximum).