what is the use of get and post??

Answer 1

both are data transfer methods, get is used where your landing page should be stable, when you visit same page by history or reload, the data will be there, as it is transferred through URL. post transfer as body, it is used when you need secure transfer like password.

Answer 2

to send your data from client ( browser) to server.

Answer 3

Both methods are for data transfer with PHP, however the GET is passed through the URL and POST is not, thus being the most secure method for use in systems.