You should add new line character between the inputs. PHP - how to create a newline character?
<?php
$to = "myemailhere@domain.com";
$subject = "Form Information";
$fname = $_POST['fname'] ;
$lname = $_POST['lname'] ;
$message = 'First Name:' . $fname ."\r\n". 'Last Name:' . $lname;
$headers = "From: $email";
$sent = mail($to, $subject, $message, $headers) ;
?>