Advertisers can exclude referrals in the new Google Analytics 4 (GA4). According to Google, the common referrals to exclude are third-party payment processors, like Stripe or PayPal, or website-managed interactions.
A third-party payment processor becomes referral when a user returns to the site after checking out on the third-party domain. The same happens for website-managed interactions, when, for example, a password-recovery operation emails a user and there is traffic from the email domain back to the website.
Advertisers can look at the referral domains in GA4, to identify traffic from a domain that should not be a referral.
By listing the unwanted referrals, advertisers have a clear view where their conversions are coming from. Without referral exclusion, most of the conversions are attributed to third-party payment processors, if a payment is done.
To exclude referrals in Google Analytics 4, advertisers need to go to Admin > Property > Data Stream > Select the Data Stream > More Tagging Settings > List Unwanted Referrals
In List Unwanted Referrals, advertisers can specify domains whose traffic should not be considered to be referrals.