To enable the new email address validation feature (preview), log in to Power Platform Admin Center >> Settings >> Features >> Data Validation

Switch On – Data Validation. (Interestingly in one of the environments enabling this setting was enough to get the smart email validation working however in another environment had to enable the below settings as well to get that working)
Next open the Model Driven App in Maker Portal – App Designer and switch on Enable Smart Email Address Validation Control

Below we can see it validating the email address while we enter its value

We get the below messages



And this works for the email field in a custom entity as well.

Refer – https://learn.microsoft.com/en-us/power-apps/maker/data-platform/data-validation-email-column
Also, check the similar feature we have for Sales Hub App
Hope it helps..





























