wordpress-php integration and template requirement

is it compulsory to make templates of my form and then apply it in my page or can i simply make form action to go and validate data from another php file in wordpress directory?...although it does function completely without any errors...buta friend told me that wordpress requires templates for forms and any php???

<form action="mypageform.php" method="post" name="myForm"     onSubmit="validateForm()">
Name
<input name="fullname" type="text" value="" />
Age
<input name="age" type="text" value="" />
Email-ID
<input name="email" type="text" value="" />
<input name="submit" type="submit" value="Submit"  />
</form>
<script type="text/javascript">// <![CDATA[
function validateForm()
{
var x=document.forms["myForm"]["fullname"].value;
if (x==null || x=="")
{
alert("Name must be filled out");
return false;
}
var x=document.forms["myForm"]["age"].value;
if (x==null || x=="")
{
alert("Age must be filled out");
return false;
}
var x=document.forms["myForm"]["email"].value;
var atpos=x.indexOf("@");
var dotpos=x.lastIndexOf(".");
if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
{
alert("Not a valid e-mail address");
return false;
}
}
// ]]></script>