What is domain verification? 

Domain Verification provides a way for you to claim ownership of your domain in Business Manager. This ownership allows you to control the editing privileges of your content to prevent misuse of the domain. This includes both organic and paid content. Domain verification is a step towards ensuring that only verified owners can edit the way the content appears on Facebook. 

Once you have verified your domain, you can assign specific Pages editing permissions for your ads. Pages associated with your Business Manager that do not have editing permissions won't be able to make changes to your ads.

Why is domain verification necessary? 

Domain verification also allows you to manage editing permissions over content in order to help prevent misuse of your domain. Managing your ad link editing permissions also helps ensure that only trusted employees and partners represent your brand.

 Apple has announced changes with iOS 14 that affect how we receive and process conversion events from business tools such as Facebook Pixel. To address these changes, we will request permissions through Apple's AppTrackingTransparency framework to measure conversion events occurring on iOS 14 devices. As more people, opt-out of tracking on iOS 14 devices, ad personalization, and performance reporting will be limited for both app and web conversion events. A key impact of this change is that you'll be limited to the use of eight conversions events per domain for optimization and reporting

Note: When you create an ad set, you can only choose one of the eight designated conversion events to optimize for.

Domain verification establishes which Business Manager account has the authority to configure and prioritize the eight available conversion events for a given domain

How can I verify my domain?

Refer here for a 15-20 minute step by step process - https://developers.facebook.com/docs/sharing/domain-verification/verifying-your-domain

In the case of a Shopify website once you have the meta tag as mentioned above go to Online Store > Themes > Actions > Edit Code > Paste the meta tag on the Head Section 

Requirements for domain verification

  • You'll need admin access to your Business Manager
  •  You’ll need admin access to your website’s root folder to use this HTML file optionDomain verification requires the webmaster for your domain to place a special code on your website