Cookies are files, often including unique identifiers, that are sent by web servers to web browsers, and which may then be sent back to the server each time the browser requests a page from the server.
Cookies can be used by web servers to identity and track users as they navigate different pages on a website, and to identify users returning to a website.
Cookies may be either “persistent” cookies or “session” cookies. A persistent cookie consists of a text file sent by a web server to a web browser, which will be stored by the browser and will remain valid until its set expiry date (unless deleted by the user before the expiry date). A session cookie, on the other hand, will expire at the end of the user session, when the web browser is closed.
WordPress Test Cookie (disappears when the website is closed)
PHP SESSION COOKIE (PHPSESSID)
The PHPSESSID cookie is native to PHP and enables websites to store serialised state data. On the Action website it is used to establish a user session and to pass state data via a temporary cookie, which is commonly referred to as a session cookie. As the PHPSESSID cookie has no timed expiry, it disappears when the client is closed.
To delete these cookies, you can go to the browser settings and delete accordingly.