Cookies are small pieces of text that a website sends to a browser and that the browser sends back upon subsequent visits to the site. They are mainly used to maintain sessions, for example, by generating and sending back a temporary identifier after logging in. However, they can be used more broadly by storing any data that can be encoded as a text string. As a result, users do not have to enter the same information every time they return to the page or navigate between pages.
wikipedia.org
| _ga | A cookie used by Google Analytics to distinguish user sessions by assigning them a randomly generated number as a client identifier. It is included in every pageview request and is used to calculate visitor, session, and campaign data for site analytics reports. |
| _gid | A cookie used by Google Analytics to distinguish users without storing any personally identifiable information. |
All modern web browsers allow you to enable or disable cookies (they are usually enabled by default). If you do not wish to receive cookies, you can change your browser settings.
Information on how to change cookie settings for individual browsers can be found on the respective developers' websites: