what is a php ? and why use php ?

Answer 1

What is PHP:
PHP is a server-side scripting language designed primarily for web development but also used as a general-purpose programming language.
Originally created by Rasmus Lerdorf in 1994, the PHP reference implementation is now produced by The PHP Development Team.
PHP originally stood for Personal Home Page, but it now stands for the recursive acronym PHP: Hypertext Preprocessor.
(source: https://en.wikipedia.org/wiki/PHP)

Why use PHP:
- Comprehensive
- Easy to learn
- Well documented
- Works good
- Free

read more:
http://php.net/manual/en/intro-whatcando.php

Answer 2

If you want to know follow the PHP course of Sololearn. It's great stuff.

Answer 3

To help handle databases with SQL

Answer 4

To handle server data which Javascript and HTML are not possible to access it.