PHP for contact form

I am trying to create a contact form that will send an email when the information is submitted. I’m in the process of creating a page template for it, but I’m not sure how to encode the php properly. Although I am well versed in html, php is very much a new animal for me on the mt platform. I know the php and the html is correct, I just don’t know how to make sure the php encodes properly on the page.