We'll create fresh WordPress site with OTP by Email for Contact Form 7 installed. You have 20 minutes to test the plugin after that site we'll be deleted.
Use this CF7 extension to enable OTP links to be inserted into confirmation/notification emails sent to email addresses submitted through your CF7 forms. The OTP is a unique link the email inbox user needs to click to confirm their address. The link is valid by default for 72 hours and can be customised.