A cookie is a small text file that is saved by the websites that you visit on your computer. 

A cookie can contain information, such as a user ID or preferences, which the websites use to personalize content, track the pages you've visited or to save your password so you do not have to re-enter it each time you visit our websites. 

A cookie can be classified by its lifespan and the domain to which it belongs. By lifespan, a cookie is either a:
• session cookie – which is erased when the user closes the browser
• persistent cookie - which remains on the user's computer/device for a pre-defined period of time

As for the domain to which it belongs, there are either:
• first-party cookies - which are set by the web server of the visited page and share the same domain
• third-party cookies - stored by a different domain to the visited page's domain. This can happen when the webpage references a file, such as JavaScript, located outside its domain

Except for session cookies that we keep only for the duration of your session, we will ask you for your consent to our use of cookies when you first visit our websites. We may assume that you consented from ticking a box and clicking on an “I agree” button (or similar). If you agree, we will place an opt-in cookie on your device. These will help us remember your choice and avoid asking you in the future. 
If you are not comfortable anymore with the use of cookies, you can manage and control them through your browser, including deleting them from your 'browser history' when you leave the site, and you will be asked again if you agree or disagree with our use of cookies when you next visit our websites.
Enabling these cookies is not strictly necessary for the websites to work but it will provide you with a better browsing experience.