A cookie is a small text file that is stored in your browser when you visit almost any web page. Its usefulness is that the web is able to remember your visit when you return to browse this page.
Cookies usually store information of a technical nature, personal preferences, personalization of content, usage statistics, links to social networks, access to user accounts, etc.
The aim of the cookie is to adapt the content of the website to your profile and needs, without cookies the services offered by any page would be significantly reduced.