A cookie is a small amount of data that the servers send to the browser. The latter saves them on the user's computer.
The browser then sends this data back to the server with each subsequent visit to the site. Cookies are normally used to distinguish individual users, the contents of the "shopping basket" in electronic stores, user preferences, etc. are stored in them.
Technically, it is a series of codes according to which the browser collects and then sends information about our behavior back to the relevant server.
Cookies contain information about how long the browser should store them (from one-time to several years).
Cookies are not directly linked to your name or e-mail address, but often contain your login data to the system. They are common to one browser installation. Cookies are not secured in any way, including the collected data.