How do I download an image/file to a specified location on the disk?
This behavior is largely up to browser itself, and this can't be controlled over how the browser has been configured.



Above settings are from Google Chrome browser. If user has checked "Ask where to save each file before downloading" checkbox, then browser will prompt to choose location else download to default location set in "Download Location".

Instead try educating the user before they download. That's the best way.

Ref : Prompt user to save file to a specific location