Joplin stores all notes within a database, which has its pros and cons. Among the cons is the fact that your notes live within a closed box. Sometimes you may want to use joplin for editing a document that you want to reside somewhere else. For instance, being a text file, markdown is nice as a software documentation format, so the current doc can be managed in a version control software alongside with the corresponding source code (I suspect github figured this out already 
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To keep going with this example, one way to do this is to have your document in joplin database and export it in md format to your application folder (with its dependencies if any) before committing your code.
What I want to suggest is a fairly simple goodie to ease such process, if you're gonna do this on a regular basis with multiple target folders.
The most minimal implementation would be to add an "export destination" field in the note properties dialog (+browse button for filling it), and when you right click -> export the note, the file browser takes you directly to this path (with the note name as default file name, or with the name specified in the "export destination" field if it also contains a file name)
A much improved implementation would be the above + a "quick md export" button in the note toolbar, which simply exports the note in md format to the destination specified in the note properties within a mouse click (no file browsing). This would make working with files that need to be stored in a specific place a breeze.
BTW, I noticed that when exporting a single note to pdf, Joplin saves it in the browsed directory, while when exporting to md, it replicates the notebook hierarchy and saves it in a subfolder of the specified destination. For instance if you want to export "book1/subbook2/note" to "c:\doc", it will save it to "c:\doc\note.pdf" but to "c:\doc\book1\subbook2\note.md". This behavior isn't desired in the quick export context: it should be exported to the root of the specified folder (with dependencies in a dedicated resource subfolder (named + "_resources" for instance). Well, actually I don't think I want it to behave like this ever unless I'm exporting a whole top level notebook...