Cookies are small files that are stored by users in browsers when a web page is visited. It allows individuals to keep what they are looking for on websites stored in their browser history. It allows a website by ensuring that the movements made on the site are kept in browser records. The first purpose of use was to check whether a user had re-entered the site he had entered. Now it is used to get more information without deviating from its main purpose. They are the files that make us remember. Since our information is also written in these files, we do not need to enter our information again by recognizing us when we log in to the same sites. Cookies contain a lot of information, including your personal information. E-mail, first name, last name, phone number, etc. it may contain information. However, the information that a site can access is limited to what you offer. Websites cannot access information that you do not provide. At the same time, no website can access other files on your computer. Usually cookies are based on your location or language preference of the websites you are interested in, etc. it is also used to store your settings. When you re-enter the site you have previously entered, it sends the cookies belonging to that site to the site again. In this way, the site is able to offer customized information to suit your needs. Each cookie is stored under separate files in Internet browsers. Only in the FireFox browser are all cookies stored in a single file in the FireFox profile folder.