What are cookies and in which language are they

Answer 1

A cookie is a piece of data that stores information which is saved on the user's system. They are useful for saving information such as visited pages, passwords, etc.
Cookies not the best practice for most modern browsers and instead you should look at other ways of storing data on the client side such as Web Storage and IndexedDB.

You can check this lesson about Cookies in php:
https://www.sololearn.com/learn/PHP/1843/

Answer 2

First tell where you heard about this? If your heard from anywhere then you can also get description or tutorial there.

https://www.sololearn.com/discuss/403415/?ref=app
https://www.sololearn.com/discuss/1506117/?ref=app
https://www.sololearn.com/discuss/1954089/?ref=app
https://www.sololearn.com/discuss/350098/?ref=app
https://www.sololearn.com/discuss/137673/?ref=app
https://www.sololearn.com/discuss/816594/?ref=app
https://www.sololearn.com/discuss/248732/?ref=app