Your all collections page can be access by either opening your Shopify store and adding: /collections to your URL or by adding a link in your main menu to the "All collections" option.
This will output the collections that you have created within your store which when clicked will open their respective collections.
By default any featured images that you have added to a collection will display here as the placeholder for that collection. If you have not added a collection featured image then the first product from each collection will be displayed instead.
The "All collections" or list collections page is a section which contains a handful of options to configure the display as this is not directly editable from within Shopify's admin.
Image - Add a banner image that will span the full width of the all collections page.
It is recommended to use an image 1920px wide x 400 - 500px tall for this.
Text - This is an area to add a text description to this page for some valuable SEO and to also guide customers through what the are viewing.
Collections per row - Choose the grid setup to show 2, 3 or 4 collections per row.
This will default to 2 per row on mobile
Show collection product count - Checking this option will display X - items on each collection informing the customers how many items are available for purchase within each collection.