How can I locate files folder/app on my 2013 iPad Pro M4?

Perhaps you have deleted the Files App from your Home Screens. If so, you should be able to locate any installed App using the App Library of your iPad; simply swipe to left from your Home Screens, the last page being the App Library.

The iPad User Guide describes both the App Library and management of your App icons:

Find and use your apps in App Library on iPad - Apple Support

If you actually uninstalled the Files App, it can be reinstalled from the App Store:

https://apps.apple.com/app/files/id1232058109

See this support page:--> Find files and folders in Files on iPad and serach for this icon:

You're very welcome.