I searched in google and come to know that there are some tools which will provide remote assistance functionality (ex:Gotoassist,teamviewer).But i want to implement the similar kind of feature in php.
Is it possible to implement in php or not?
I'm going with NOT just in PHP, PHP is a server side scripting language.
https://www.php.net/manual/en/faq.general.php#faq.general.what
PHP can be responsible for hooking the session up / starting a server repeater and helping your user to connect with you - but it can't physically do the drawing of client side screen graphics and mouse/keyboard operation - you need something like this:
http://phpremotesupport.com/about/
In tandem with a VNC viewer or other remote viewing product (C, C++, C#, .NET VB would be used to program it most likely) - found this one which might be useful to you called noVNC (web-based): http://kanaka.github.com/noVNC/