After your store is approved, the option to tag products will be available for every new story, new post, and your previous posts. To get started, create or edit an Instagram post, and click Tag Products. For help, visit Instagram's documentation.
Keep in mind:
When you add a new product to your store, it'll be available to tag on Instagram
After you tagged a product in a post, a shopping bag icon appears on the post. Instagram users can tap on the post to view the tagged products, and then click a tag to view:
A product photo
Product name
Price - If variants of the product have different prices, the lowest price will display. The sale price won't display.
A Shop Now button that opens the product on your site.
Choosing a selection results in a full page refresh.