Question:Write down the all WordPress roles and capabilities. 

1. Administrators: can do anything in the WordPress administration area: write, edit, and delete posts, pages, links, and comments, upload media files of any type; import content, manage the Dashboard; create, edit, and delete other users; enable and configure plugins and themes; change the site’s theme; and manage all the available options. If you installed WordPress, you are an administrator.2. Editors: can publish, edit, and delete posts and pages written by any user. They can upload some kinds of files, and they can write HTML without restrictions. They can manage links and categories, and they can moderate comments. Editors and administrators are also the only users allowed to read private posts and pages.3. Authors: can publish, edit, and delete their own posts. They cannot write pages. They can upload some kinds of media files, and they are allowed to use only the limited set of HTML tags.4. Contributors: can write their own posts but may not publish or delete them. Their HTML is limited to the set of allowed tags and they cannot upload media files. Contributors’ finished posts are saved as Pending Review until an editor or administrator approves and publishes them.5. Subscribers: can manage their own profiles, but can do virtually nothing else in the administration area.

Question:Write down the step of changing the permission of WordPress user roles? 

The WordPress role system is very granular; individual capabilities can be added and removed, and whole new 
Roles created through the administration screens. The Members plugin is the most complete and up to date plugin for managing roles and capabilities.
To change the user permission go to Members plugin > select Edit Role > select Role Name > and checked desired Capabilities option(s).