You can embed one public Instagram Reel on a Shopify page in five minutes with Instagram's own
Instagram's official embed code still works for a single public Reel and needs no app, no API and no business account.
The embed is an iframe that is not lazy-loaded and cannot tag a product, so it suits a blog post or About page more than a product page.
Paste the code into a Custom Liquid section on Dawn or Horizon, not into the page's rich text editor, which strips scripts.
For product pages, or more than a couple of Reels, an app widget imports the Reel as a lazy-loaded video with add-to-cart inside the player.
Yes. Open the Reel on instagram.com, choose Embed from the menu, copy the code and paste it into a Custom Liquid section in the theme editor.
The full guide has the formats, the deadlines and the worked examples.