PHP e-mail form From address is server

Hi Guys, This is my first post here so hello to everyone,
I’m trying to setup a PHP contact form, I am currently testing it on my Mac because I don’t want to go through installing PHP on our domain controller/web server and not have it work. Whenever I send a message the From address is always my Mac’s name and shows up as _www@Kyles-MacBook-Pro.local.

Can anyone tell me how to make my PHP script fill in that space with the e-mail field from the HTML form?

Thank You