You can edit files on the Windows side (
C:\xxx) and access them from Debian (
/mnt/c/xxx), that's no problem. You can even start Notepad++ from bash which opens in Windows as usual, but as you can't edit any linux files that doesn't make any sense.
So in order to edit files of your linux filesystem you will have to copy them to a shared windows directory
/mnt/c/whatever first, edit them there and copy them back afterwards.
Another possibility would be to install samba on linux and mount your work-directories in Windows. The other way around accessing a Windows share using smbclient is also possible, but no fun using commandline linux, already tried that. You are faster copying your files.
Or you use emacs, vim, ...