I would like to add custom fields to the approval emails, which have the "Approve" and "Decline" options embedded in the email body. When an approver is notified, they should be able to see what they're approving.

These are the default fields, but it's not enough information for an approver to take action on.

For this to be effective, we would need the ability to add different custom fields based on request type.
For this to be simple, we should be able to click a button that says, "add all custom fields per request type". With this, we would not have to maintain the approval email when fields change or different request types are used.