PHP was started as a small open-source project that evolved when more and more people came to know about its advantages and usefulness. The first version of PHP was released by “Rasmus Lerdorf” in 1994. For Students and professionals to become software engineers PHP is a must especially when they are working in Web Development Domain. We can Run PHP on different platforms for example Linux, UNIX, Windows, etc. It is also compatible with almost all the servers used today like Apache, IIS, etc. PHP is easy to learn and runs efficiently on the server-side. 

• Advantages of Learning PHP –

1. PHP is a server-side scripting language like ASP that is embedded in HTML. The scripts are executed on the server. PHP can be used to manage the dynamic content, databases, session tracking, and for building an entire E-commerce site.
2. PHP supports many databases that are PHP is integrated with the databases like MySQL, PostgreSQL, Oracle, Sybase, etc.
3. PHP supports a large number of protocols like POP3, IMAP, and LDAP.
4. PHP4 has made possible the n-tire development for the first time. By adding support for JAVA and distributed object architectures (COM and CORBA).
5. PHP when executed becomes zippy especially when we compile PHP as an Apache module on UNIX. 
6. PHP combined with MySQL are cross-platform that is you can develop on windows and server on a UNIX platform. The MySQL server executes complex queries with huge results sets in record-setting time.
7. PHP has a C-like Syntax.
8. PHP tries to be as forgiving as possible. 

• Common uses of PHP-

1. PHP can perform System Functions. For Example, if there are files on a system it can create, open, read, write, and close them.
2. PHP can handle Forms that is it can gather data from the files, then save the data to the file, you can send data through email, and can return data to the user. 
3.   With PHP you can add, delete, and modify elements that are in your database.
4. PHP can access cookies variables and set cookies.
5. PHP can restrict some users from accessing some pages of your website.
6.  PHP can encrypt the data.

• Characteristics of PHP- 

 Because of the following characteristics, the practical nature of PHP has become possible-

1. Simplicity
2. Efficiency
3. Security
4. Flexibility
5. Familiarity

• PHP file – The files of PHP contain text, html tags and scripts and are returned to the browser as plain HTML. The file extension used for PHP files is “.php”, “.php3”, or “.phtml”.