You should be an admin user to generate a business admin key. If you are already an admin user, go to settings>>admin>>search for your admin>>click on your admin name as shown below.
Once done, go to the bottom section where you will get the option to generate your business admin key as shown below.
Once generated, you can use this admin key to hit Punchh Dashboard APIs. Please note that your admin user role should have Dashboard API access permission enabled to use this business admin key to hit our Dashboard APIs.
If further assistance is required, submit a ticket to Punchh Support. (For help submitting a ticket, click here)