Unsubscribe link inside the email

Can you please provide a sample code so that I can enable “Unsubscribe link” inside my email. I have tried with these:

your unsubscribe text here
your unsubscribe text here
your unsubscribe text here
your unsubscribe text here

but none of these is working?

Thank You in advance!
Благодаря ви предварително!

https://wordpress.org/plugins/e-mail-broadcasting/