The Settings tab in WordPress Admin sidebar is the central hub to configure settings for different sections of a WordPress website. It contains multiple sub-panels and many WordPress plugins also add their settings page as a menu under the Settings tab. Clicking on it takes users to the Settings » General screen. Other default sub panels under the settings tabs are Reading, Writing, Discussion, Media, and Permalinks.
Only a user with the administrator user role has the access to the settings tab.
General contains settings such as Site Title, Tagline, WordPress URL, Site URL, E-mail, Registration option, and many other general options for the WordPress site.
Writing contains settings related to the post formatting and category options.
Reading contains settings related to Site Front Page, How many posts to show per page to readers, RSS items to be shown, whether full text or summary should be shown, and an option to discourage search engines from indexing the website.
Discussion contains settings related to linking posts with other blogs that are referenced, comment settings, e-mail notifications for comments, and options for comment moderation.
Media contains settings related to upload and management of images and other media within WordPress. Things like image sizes and cropping options can be managed here.
Permalinks contains settings related to URL structure of the website. These settings make it easier for users to find and remember URLs to specific posts. Using the correct structure will also help to better organize posts within the various categories. Options in this setting allow you to control whether you want dates reflected in your URLs or just titles and categories, or some combination of both.