How to send a response message to particular employee

Question

I am trying to create a human approval process using AWS step function. In this process after executing a State machine manager get a mail from employee side with links for approval or rejection of their promotion request. I want that whenever manager click on any one of the link employee get an appropriate mail regarding their request status. How can I implement it

I want to send a response mail to the particular employee when manager click on any of the link