What file is modified when changing Print Defaults using cups?

I believe that file is in /etc/cups/ppds or somewhere in a similar path. You can always use Jamf Printer Manager to capture the settings directly Jamf Pro too.

https://github.com/jamf/jamf-printer-manager

You can map and modify printers using CLI with Cups and just use a script, but as @talkingmoose suggested I would just use Jamf Printer Manager and take the lazy way out.

I like to think of it as being "efficient". ;-P

I looked at Jamf Printer Manager and I don't see how to set any of the Printer Defaults (like you can using 127.0.0.1:631/printers

We already have our Follow Me printer installed on our computers, but the Printer Default is 2-Sided Color. I would like to give the option to staff to have the default 1-sided BW Staple Free, and from there, they can create their own Presets to change those settings.

Actually, I would like to create Self Service options for 1-sided BW Staple Free, 2-sided BW Staple Free, 1-sided Color, 2-sided color, etc and let staff select what they want as a Printer Default.

Just don't know how to go about doing this.

Printer Manager isn't used for setting printer defaults. It replaces the printer functionality from Jamf Admin.

You need to configure a printer on your computer and point it to the correct PPD to give you the list of possible options like duplex, stapler, extra paper trays, etc.

You'll use Printer Manager to capture those printer settings and add them to Jamf Pro to deploy to other computers.

So… how do you set the Printer Defaults. Better yet, how do you create a Self Service 'app' to set the Printer Defaults?

You need to add and configure one computer with a connection to the printer in Settings > Printers & Scanners. Be sure you install any printer manufacturer software first. This usually includes PPDs (printer description files that include a list of possible configuration options like duplexing, hole punch, extra paper trays, etc.).

As part of that configuration you'll choose they type of printer, which is effectively choosing the PPD and then you'll see the options available for you to select. Depending on the printer, you may need to manually set these options. You can usually print a setup sheet from your printer to help you know what options it has available.

Once you've configured the printer on your computer, use Printer Manager to capture the printer and its settings and upload them to Jamf Pro for deployment using a policy.