Don't believe that free hosting accounts can actually make changes to the php.ini file, not that you actually need to do this in order to send mail using the 'built in' php mail function. It's all quite painless code.
HTML Code:
<?php
$to = "someone@example.com";
$subject = "Test mail";
$message = "Hello! This is a simple email message.";
$from = "someonelse@example.com";
$headers = "From: $from";
mail($to,$subject,$message,$headers);
echo "Mail Sent.";
?>
Above Source From W3 Schools
What I will say however is that the x10 servers are a little 'quirky' depending upon other users demands throughout the day, but it has been getting better.. Sometimes email may take a long time to send or often not send at all.
A more reliable method is to use a mail Class script that will 'talk' to a more reliable email service like Gmail.. Email mail() Alternative and let them handle the mail for free.
You would need to read any documentation you can find for that link above to figure out if anybody has had it working with AOhell