Hi,
When you click on confirm email button present on profile page, it redirects to the page that is shown in below screenshot.

On click of the "Confirm Mail" button in the Profile page, the "Send Email confirmation to Contact" workflow is triggered which is shown in below screenshot.

And below is the screenshot of mail being sent from the above mentioned workflow.
Note : The email would be received to the users only if email configuration is been setup for the CRM user who is set as "Sender" of email mentioned in the "From" field in below screenshot.

You can view the email under contact’s timeline in model driven app as well as user’s registered email inbox.

And below is the mail received in gmail

Once you click on Complete Registration link from your email which was received, then in portal it will show you the message that "Your email has been confirmed successfully" as you can see in below screenshot.

Hope this helps!!!
If you find this solution helpful, please mark it as accepted solution.
Thanks!
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