Only sort of the right place to put things

SpecialFolder.ApplicationData initially seems a great place to store your applications runtime data. But its only sort of the right place to put things

In reality its the right place for ALL applications to put their data. And becuase many applications can and do put their data there a good habit to get into is to create a DIRECTORY, or folder, specifically for YOUR application to put its things in rather than just toss all of the bits you might want to save in SpecialFolder.ApplicationData (and hope no other app saves over it, erases it, alters it, etc)

There are several ways to accomplish creating a directory for your application and it will depend on what OS your on as to which is “more correct”.

One macOS it might be a good thing to use your applications bundle ID for the name of the directory.
One Windows, while you can use that same string it might be nicer to use the actual name of the application
I’m not 100% sure of what the correct convention is for Linux but you may want to create it as one with the name starting with a period so its hidden by default.

Tim Parnell has a nice module for making some of this really simple to do.

Your users will appreciate it