A cookie is a file (a string of data) that can be created by the program displaying the website on the website visitor's computer, mobile phone or other device providing Internet access. The cookie is sent by the web server to the visitor's browser, and then the browser sends it back to the server. Cookies only contain data, that is, they do not contain executable files, viruses, or spy programs (spyware) and do not have access to the data of the user's hard drive.
(A cookie is a coded string of data, an access path that can only be interpreted together with the given server. The user's data is stored by the server, not the cookie. (All websites use cookies.))