Email

How to use email plugin in contact us, i mean to what url i should post the request ?

Hi, how did you create the "contact us" page? Are you using a custom form or using a Grav plugin?

custom form actually, i have added grav email plugin in to my plugin-folder too.

Have you taken a look at http://learn.getgrav.org/advanced/contact-form and http://learn.getgrav.org/advanced/forms ? There's a built-in functionality in the Form plugin that allows you to send emails.