You can control the look and feel of your collection pages using tools within your theme editor.
Open: themes > Customize theme While looking at the theme navigate to a collection page
In the left sidebar you will see some of the following options:
Products per row - Choose how many products will be shown per row ( defaults to 2 on mobile )
Rows - How many rows of products will be shown per page. Note that Shopify's collection pages will only show a maximum of up to 50 products before pagination will be added to the page
Show sort by - Allow customers to sort how they see your products
Filters - Filters allow customers to refine the view of products within a collection based on tags that you will add to your products, for full details and instructions please see our guide
Content - Adding content such as a menu or a Vendor list will automatically add a sidebar to your collection pages. Adding menus will give additional navigation options to your customers which are advisable for stores with large inventory.