There are many different WordPress plugins and code snippets you can use for adding a ‘scroll to top’ button in your WordPress site. A ‘scroll top top’ button simply allows your readers to instantly move back to the top of the site (header) as soon they click it, it uses JavaScript s the page doesn’t get refreshed every time.
WordPress plugin’s repository has a new plugin called Simple Scroll To Top. Simply install and activate the plugin and you are done. Visit the frontend of your website, scroll down and see how it works.