Managing Your Digital Stuff - Clear (Browser)
History and Website Data

Wikipedia: Web browsing history
  Web browsing history refers to the list of web pages a user
  has visited, as well as associated data such as page title
  and time of visit. It is usually stored locally by web
  browsers in order to provide the user with a history list to
  go back to previously visited pages. It can reflect the
  user's interests, needs, and browsing habits.
Wikipedia: Cookie   
  A cookie is simply a small file that a web site places on
  your computer to store information. The process itself is
  totally benign, and can even be helpful-cookies do useful
  things like store your shopping cart information between
  sessions, save you from the hassle of logging into a site
  every time you open and close your browser, and other
  helpful time savers. 
  The ones that give cookies a bad name track users without
  their explicit knowledge and help advertisers (or other
  entities) build profiles of users. Many people want to limit
  the amount of information that is gathered about them, and
  do so by limiting the kind of cookies that their browser
  accepts and retains.

Regularly Delete History And Website Data (includes cookies) Removing cookies and more. Wipe your computer of your browsing history, cookies, and other detritus. It won't solve the problem on its own, but it is almost essential to clear away the tools people can use to track you. On Mac: Safari > Clear History... On iPhone & iPad: Settings > Safari > Clear History and Website Data Android: Manage & delete your Search history Don't know how to delete history and website data on your browser? Just go to a search engine like DuckDuckGo and type, "How do I delete history and website data on Firefox (Chrome, or whatever)?"
Firefox: Delete browsing, search and download history Getting Rid of Evercookies from Safari Not all these elements can be deleted by a user, although routinely deleting your caches can help. In macOS with Safari, you've got two options: light and nuclear. For the "light" option, in Safari choose Safari > Clear History and select All History from the popup menu, and a huge number of items get wiped out, including visited pages and browser cookies. Wiping history deletes it across all linked iCloud accounts, too. The nuclear option requires enabling the Develop menu in Safari > Preferences > Advanced. Check Show Develop Menu in Menu Bar. From the Develop menu, choose Empty Caches. There's no warning or going back once you select the item. This deletes all local storage, all browser cookies, and everything cached relatived to the Web browser. Close all tabs, nuking the caches, erasing history, quitting the browser, and relaunching revealed no evercookies hiding. We're Getting Buried in Browser Tabs And Scientists Want to Fix It A small new study has found many people who browse the internet experience tab overload, saving articles to read later, leaving tasks as reminders, or burrowing down an internet hole until the stack of open web pages becomes impossible to navigate. The clutter can make people feel stressed, distracted, shamed, and overwhelmed. Despite this, we often avoid clearing up the mess. Related: OLLI Class: Privacy When Using the Internet