What cookies are
Cookies are small text files placed on your device when you visit a website. They help a site remember your actions and preferences over time. Some are necessary for the site to work, and others help us understand how it is used.
A cookie is not a program and it cannot run on your device on its own. It holds a short piece of information — a setting you picked, or a session identifier — that the site reads the next time you load a page. Cookies are stored separately for each browser and each device, so a preference saved on your phone will not follow you to a laptop unless you sign in with a service that links the two.
Two time frames matter. A session cookie is removed when you close the browser. A persistent cookie stays for a set period, which is what lets a site recognize you on a return visit. You can clear either kind from your browser settings whenever you want, and the site will simply treat you as a new visitor on your next visit.