How to Enable Sign In with Shop in Shopify Horizon Theme

Sign in with Shop lets returning shoppers skip manual account creation and autofill their details via the Shop app — Horizon supports it natively at checkout and account entry points.

Steps

1. In your Shopify admin, go to Settings > Checkout and make sure Shop Pay is enabled for your store — this is the underlying requirement, not a theme setting.
2. In your Shopify admin, go to Online Store > Themes and click Customize on Horizon.
3. Check your account/login page and buy button block settings for a Sign in with Shop option, and turn it on if it isn't already.
4. Click Save.

This feature depends on Shop Pay being available in your market and currency — if it doesn't appear as an option, that's usually a Shop Pay eligibility issue rather than something wrong with the theme setup.