To configure your Product Per Page, please go to Dashboard > Appearance > Customize > Shoppable Pro Woocommerce > Archive/shop.
It’s used to display the number of products per page on the archive/shop page.
It is possible to enable user select box for archive/shop page, where can the users define number of visible products. To do it go to Customize > Shoppable Pro Woocommerce > Archive/shop and enter the number at “Number Of Items ”. Then, enter the second number in the “Second number” field.