A common misconception is that additional PHP can be run upon the user doing something (i.e. clicking submit button). Not the case. When the page has been rendered, no further PHP on that page can be executed.
So, what to do?
You have two options:
(1) You can create a second page (action_page.php
or some name), that is specified on the action=
attribute of the form tag. That additional page will receive the data the user typed in, via PHP variables $_POST
(if method="post"
) or via $_GET
if method=get, and you can then use that data to send the contact form, and either display new data to the user or send the user back to the original page. Of course, you may need additional PHP to acknowledge the form has been sent, etc - and this additional code will need to handle both the case where the user is visiting the page for the first time, and when the contact form has been sent and the user is seeing the page for the second time.
(2) You can use AJAX (javascript/jQuery) to grab the form data, send it to a secondary PHP file, which will receive the data via the $_POST/$_GET variables, send the email, and return a response back to the first page.
These days, mostly we use the second method, because it is much more powerful. For one, the user remains on the same page. For another, there is no page refresh. For another, your javascript can do other things after the form has been sent.
AJAX is actually pretty simple - just do a google search for YouTube videos on creating a login system with PHP and AJAX. You should be able to find one of around 10 mins or less that explains all you need to know to send your contact form, and send feedback back to the calling page.
Here is a 5-minute YouTube tutorial that will show you the basics:
Install a simple PHP and Ajax login system