You will need some server-side technology: ASP.NET, JSP, PHP, Python — you name it.
You can have an HTML form to get some mail data from your user. The form can have "POST" method to perform HTTP post to your HTTP server with some target URL. Everything else depends on what you have on the server side.
Please be advised that sending e-mail from the post data is a really dangerous business. You should get to it only if you have sufficient security experience, otherwise someone will turn your host into a zombie distributing spam or something like that. It can be done easily, in no time, unless you fully control the post data. For further detail, please see my past answer:
unable to send mail , it showing the error in below code .
You can get more help if you decide on a particular server-side technology.