Why am i not able to see any files in my Files application under "on my iphone" option??

Yes...you got it....OK. So now i understand Apple/iPhone does not reveal any file storage structures. Not even things like application data related files like Whatsapp or Facebook files. I wanted to clean the storage up as it was filling up with gigs of data ( good business for Apple/icloud storage space selling). , so. and I was told (by Apple support actually) that the only way is to DELETE those apps and REINSTALL those apps...which seems rather tedious workaround! Thanks for your help . Appreciate it!