Hi Chauhan,
Welcome to our forum.
Google is full of projects using a PN3906 transistor but don't say which company makes it. I think that it is some company's house-numbered 2N3906 transistor. The datasheet for the 2N3906 is available with a Google search, go to www.google.com or click on the WWW Search link under my name or the button at the bottom of this page.