Cookies are small text files that a website places on your device — computer, tablet, or mobile phone — when you visit it. They are widely used to make websites work, to work more efficiently, and to provide information to the owners of the site.
Cookies can be session cookies, which are deleted when you close your browser, or persistent cookies, which remain on your device for a set period or until you delete them. They may be set by the website you are visiting (first-party cookies) or by third-party services operating on that page.