You can add a Facebook pixel ID to the preferences of your online store in Shopify admin to integrate the pixel with your online store. Using this integration doesn't require you to edit your online store code.
1. From your Shopify admin, go to Online Store > Preferences
2. In the Facebook Pixel section, click Set up Facebook.
3. Click Add sales channel.
4. In the Facebook account section, click Connect account.
5. In the Business Manager section, click Connect to connect the Business Manager you use to manage your business Page, accounts, and product catalog.
6. In the Ad account section, click Connect to connect the ad account your ads will be billed to.
7. In the Facebook Page section, select the business Page you want to use to sell products or post ads, and click Connect.
8. In the Facebook target country section, select a target country/ region you want to focus on from the drop-down menu.
9. Accept the Terms and conditions, and click Finish setup.