I wish to scrape news articles of the local newspaper. The archive is behind a paywall and I have a paid account, how would I go about automating the input of my credentials?
You can't access page behind paywall directly because that page may require some authentication data like session or cookies. So you have to first create these data and store it so that when you pass request to secure pages you pass require data as part of request and also have authentication session data. 
To get authentication data you should scrape login page first. Get the session info,cookies of login page and pass login input as a request (get or post based on form action type) to action page. Once you will be logged in store authentication data and use this to scrape pages behind paywall.
How to scrape a website behind a paywall