Does SPO support collections?
Yes! Starting from Dec 2018, SPO will support optimizing collections. You can set Facebook or Twitter link preview, conduct keyword research, optimize product content just like what you did for products. You can access the feature in "Collection" tab in SPO.
If you are inside the Shopify portal, you can directly edit a collection with a shortcut here. Just click "More Actions":
At the moment, the feature may not be very stable. Please contact us if you find any issues. We will try to troubleshoot for you asap.