"Products on Instagram is a new feature that allows customers with online stores to tag products from their Squarespace stores in Instagram posts. This feature is available on the Commerce Basic and Advanced plans.
This is great for clients with large social media followings, and for up-and-coming merchants who want to use social media in their sales strategy.
To tag products with Shopping on Instagram, users will use their Squarespace store’s unique data feed to sync their inventory with a product catalog in Facebook Business Manager 2. Once their Instagram and Facebook accounts are set up correctly, and they receive approval from Instagram, they’ll see an option to tag products in their Instagram business account."
- Squarespace Circle