General File Uploader

Hello,

I need to know how to be able to upload any files to the Commerce environment.

I need to host a javascript file for example. But it could be a .css file, a jQuery file, a .pdf file etc. But the system doesn't let me upload any files that aren't images (.jpg / .png etc.). I understand there are probable workarounds to be able to apply code specifically to the config settings, but I want to specifically know how to upload any file I want to my website. 

I need to see like a File Manager on our backend. Where is it possible to see this and upload files to my Commerce environment?

Thanks,