When running rake routes I see:
Prefix Verb URI Pattern Controller#Action
articles GET /articles(.:format)
Paths
I'm not sure why it's called prefix - it should be called path helper:

The bottom line is when you call helpers like link_to or form_tag etc - they will require paths to populate different actions in your app's routing structure.
As Rails favours convention over configuration & DRY programming, meaning if you can reference these path helpers over using standard urls, it will allow you to make one reference & chance the route as required
EG
Calling articles_path is far more powerful than referencing /articles every time
Routes
To answer your question properly, you will need to appreciate Rails uses resourceful routing - basically meaning that every route helper you create should be defined around any resource in your application
Due to the MVC structure of Rails, these resources will typically be defined by the controllers you use:
#config/routes.rb
resources :articles #-> articles_path etc
You should always reference your resources as they are (in your case articles).
To customize the path helper, you'll need to change the reference in the routes file, like this:
#config/routes.rb
resources :articles, as: :document, path: "document" #-> domain.com/documents
This allows you to define custom routes / path helpers, allowing you to call those as you wish