#!/bin/bash

# Run the jamf policy command
jamf policy

# Exit the script
exit 0

or just use   jamf policy

(without the sudo) in the files and processes payload 

If you want to run a specific policy then use:  jamf policy -id {id number}

You can get the ID number from the URL of the policy in Jamf Pro (e.g. ........../policies.html?id=684&o=r)

Since the Policy ID can't be reassigned if a policy is accidentally deleted, I almost always use the Custom Trigger option. Then you could use "jamf policy -event WhatEverYourTriggerIs".

Use the file and process payload in the policy add sudo Jamf policy in the execute command and make it available in self service