Scraping PDF's from a password protected website
It's certainly possible. As the other answer suggests you will want to use libaries like Requests (Handle HTTP requests) or  Selenium (AUtomated browser activity) to navigate through the login.
You'll need to sort through the links on a given page, could be done with beautifulsoup ideally (An HTML parser) but could be done with selenium (Automated Browser activity).You'll need to check out libraries like requests (To handle HTTP requests) for downloading the pdf's, the OS module for sorting the folders out into specific folders and replacing files.
I strongly urge you to think through the steps, But I hope that gives an idea about the libaries that you'll need to learn abit about. The most challenging thing to learn will be using selenium, so if you can use requests to do the login that is much better.
If you've got a basic grasp of python the requests, OS module and beautifulsoup libraries are not difficult things to pick up.
I work in tech support and currently have to manually keep our manuals for products updated manually by periodically checking to see if it has an update and if it does replacing the current one saved on our network.
I was wondering if it would be possible to build a small program to quickly download all files on a suppliers website and have them automatically download and be sorted into the given folders for those products, replacing the current PDF's in that file. I must also note that the website is password protected and is sorted into folders.
Is this possible with Python? I figured a small program I could perhaps run once a week or something to automatically update our manuals would be super useful (and a learning experience).
Apologies if I haven't explained the requirement well, any questions let me know.