How to upload pdf or, docs in safari or any popular browser in iOS?
Yah, mobile Safari does not support file uploading, even via a web upload form... sigh. However there are a number of ways to upload from an IOS device. here are two:

Dropbox, this has the benefit of having access to a large number of files and is free for most, depending on how many files you have. But you cant upload to web forms directly from Dropbox.
iCab, I've used this browser for a couple of years for just the reason you indicate. It allows you to upload (and download) files. I have not needed to do it for a while so I am not sure about the source for the files to be uploaded but I am pretty sure it includes Dropbox. It's not free but only a couple of bucks and well worth it.