What is a cookie?
A cookie is a small file that are stored on users computer or smartphones when accessing a website. It allows the website to recognise the device and store some information about the user’s preferences or past actions. Typically cookies are used to log in users or for tracking actions on a website which can be sent to an analytics platform such as Google Analytics.
As a website owner…
You must also get the user’s consent. Consent can be implied, but must be knowingly given.
There is an exception for cookies that are essential to provide an online service at someones request (e.g. to remember the contents of a shopping basket, or to ensure security in online banking).