How to Insert Custom Link on the email from OTM and then update Status back on Shipment?

Summary:

We have a requirement were an Email will be sent to Contact once Bid is finalized for a Shipment.

That email will have details such as Origin details, Destination details and Cost for the Shipment

Once the email is sent to the user, he shall review and approve the Cost

For Approving the Cost, we are having a Custom Status's - COST_NOT_APPROVED(Initial), COST_SENT_FOR_APPROVAL, COST_APPROVED

We are able to get Origin details, Destination details and Cost for the Shipment on the email, we want to know how we can insert the link and also clicking on the link if we can update the Status on the Shipment (COST_APPROVED)