How to read credentials of a website where user is already registered?

How to read credentials of a website where user is already registered and is being redirected to some page on login as credentials are being read from the machine?

I have the code where I can read the data from some dummy website but in my case, I want to read it from the website that has some login credentials. I tried using csrf reading way but the application is in django, so they have stopped csrf attacks. Please suggest

I am looking for the way explained in links like - https://www.reddit.com/r/learnpython/comments/5r0wd1/scrape_a_website_securely_that_requires_a_login/ . But the challenge is form_data = {'username': 'myusername', 'pass': 'secretpassword'}

How can I get myusername and secretpassword and again I am back to square one because of this. Can someone please help?