Squarespace Commerce is a set of features for selling products and managing orders online on SquareSpace. You can publish and automatically sync products between SquareSpace and your store. Tracking details can be entered by the vendor through a vendor portal, as SquareSpace doesn't currently allow orders to be synced.
To sync with SquareSpace, you need to just enter the URL for the shop into Jetti. No additional authentication details are required.
Note: This should be the URL for the shop, not the URL for the site. e.g. https://mystore.com/shop