How to create a php to stre the html form details

i cant able to send the submitted message in my form to my gmail id:

this is my html form which is perfectly working

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>IDECON2K19</title><script type="text/javascript">
function validate()
{
	if(document.signup.fname1.value=="")
	{
		alert("Please Enter First Name!");
		return false;
	}
	if(document.signup.lname1.value=="")
	{
		alert("Please Enter Last Name!");
		return false;
	}
	if(document.signup.uname1.value=="")
	{
		alert("Please Enter User Name!");
		return false;
	}
        if(document.signup.ph1.value=="")
	{
		alert("Please Enter phone no.!");
		return false;
	}
	if(document.signup.fname2.value=="")
	{
		alert("Please Enter First Name!");
		return false;
	}
	if(document.signup.lname2.value=="")
	{
		alert("Please Enter Last Name!");
		return false;
	}
	if(document.signup.uname2.value=="")
	{
		alert("Please Enter User Name!");
		return false;
	}
        if(document.signup.ph2.value=="")
	{
		alert("Please Enter phone no.!");
		return false;
	}
        if(!document.signup.agree.checked)
	{
		alert("Please enter the checkbok!");
		return false;
	}
	alert("Details Entered Successfully");
        display();
}
function display()
{
document.writeln('Registration Successfull!!!!');
}

</script>
</head>
<body align="center" background="images\wall.gif">
<table width="100%" height="100%">
<td colspan="2" width="15%">
</td>
<td colspan="1" background="images\new1.jpg" width="70%" height="100%" border="5%">
<h1 align="center"><font color="#0066ff" >IDECON2K19</font></h1>
<h2 align ="center"><font color="#0066ff">
REGISTRATION FORM</font></h2>
<form name="signup" onsubmit="return validate() method="post" action="form_php.php"">
<font face="verdana,arial,helvetica,sanserif" color="#660000" size="2">
<p>&nbsp;&nbsp; Person 1<br/>
*First Name:<input type="text" name="fname1" size="20">&nbsp;&nbsp;
*Last Name:<input type="text" name="lname1" size="20"></p>
<p style="border">&nbsp;&nbsp;
*Email:<input type="text" name="uname1" size="20">@gmail.com</p>
<p style="border">&nbsp;&nbsp;
Gender:<input type="radio" name="gen1" value="male">Male<input type="radio" name="gen" value="female">Female</p>
<p>&nbsp;&nbsp;
Department:<input type="text" name="dname" size="20"></p>
<p>&nbsp;&nbsp;
College Name:<input type="text" name="cname" size="20"></p>
<p>&nbsp;&nbsp;
Ph.no:<input type="text" name="ph1" size="11"></p>
<p>&nbsp;&nbsp; 
 Person 2<br/>
*First Name:<input type="text" name="fname2" size="20">&nbsp;&nbsp;
*Last Name:<input type="text" name="lname2" size="20"></p>
<p style="border">&nbsp;&nbsp;
*Email:<input type="text" name="uname2" size="20">@gmail.com</p>
<p style="border">&nbsp;&nbsp;
Gender:<input type="radio" name="gen2" value="male">Male<input type="radio" name="gen" value="female">Female</p>
<p>&nbsp;&nbsp;
Department:<input type="text" name="dname2" size="20"></p>
<p>&nbsp;&nbsp;
College Name:<input type="text" name="cname2" size="20"></p>
<p>&nbsp;&nbsp; 
Ph.no:<input type="text" name="ph2" size="11"></p>
<p>&nbsp;&nbsp; 
Idea Category:<select name="Idea Category">
<option selected>Select Category</option>
<option name="Country" value="IT based">IT Based</option>
<option name="Country" value="ECE&EEE based">ECE&EEE Based</option>
<option name="Country" value="Mech based">Mech Based</option>
<option name="Country" value="Civil&Other based">Civil&Other Based</option>
</select>
</p>
<p>&nbsp;&nbsp;
Idea Description:<br/>
<textarea name="message" rows="10" cols="30">Enter your idea description around 150 char here.</textarea>
<p align="center"><input type="checkbox" name="agree">registration fee 100Rs(for each) should be paid onspot</p>
<p align="center"><input type="submit" value="submit"><input type="reset" value="reset" /></p>
</font>
</form>
</td>
<td colspan="2" width="15%"></td>
</table>
</body>
</html>

this is my php code to recieve the email but its not working

<?php
if(isset($_POST['email'])) {
     
    // CHANGE THE TWO LINES BELOW
    $email_to = "idecon2k19@gmail.com";
     
    $email_subject = "website html form submissions";
     
    $first_name1 = $_POST['fname1']; // required
    $last_name1 = $_POST['lname1']; // required
    $email_from1 = $_POST['uname1']; // required
    $phone1 = $_POST['ph1']; // not required
    $gender1 = $_POST['gen1']; // required
    $dept1 = $_POST['dname1']; // required
    $collegename1 = $_POST['cname1']; // required
   
    $first_name2 = $_POST['fname2']; // required
    $last_name2 = $_POST['lname2']; // required
    $email_from2 = $_POST['uname2']; // required
    $phone2 = $_POST['ph2']; // not required
    $gender2 = $_POST['gen2']; // required
    $dept2 = $_POST['dname2']; // required
    $collegename2 = $_POST['cname2']; // required
     

    $email_message = "Form details below.\n\n";
     
    function clean_string($string) {
      $bad = array("content-type","bcc:","to:","cc:","href");
      return str_replace($bad,"",$string);
    }
     
    $email_message .= "First Name1: ".clean_string($first_name1)."\n";
    $email_message .= "Last Name1: ".clean_string($last_name1)."\n";
    $email_message .= "Email1: ".clean_string($email_from1)."\n";
    $email_message .= "Telephone1: ".clean_string($phone1)."\n";
    $email_message .= "gender1: ".clean_string($gender1)."\n";
    $email_message .= "department1: ".clean_string($dept1)."\n";
    $email_message .= "college name1: ".clean_string($collegename1)."\n";
    
    $email_message .= "First Name2: ".clean_string($first_name2)."\n";
    $email_message .= "Last Name: ".clean_string($last_name2)."\n";
    $email_message .= "Email: ".clean_string($email_from2)."\n";
    $email_message .= "Telephone: ".clean_string($phone2)."\n";
    $email_message .= "gender: ".clean_string($gender2)."\n";
    $email_message .= "department: ".clean_string($dept2)."\n";
    $email_message .= "college name: ".clean_string($collegename2)."\n";
    
    $email_message .= "Idea category: ".clean_string($ideacategory)."\n";
    $email_message .= "Idea description: ".clean_string($ideadescription)."\n";
     
     
// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
@mail($email_to, $email_subject, $email_message, $headers);  
?>
 
<!-- place your own success html below -->

Thank you for contacting us. We will be in touch with you very soon.
 
<?php
}
die();
?>

pls someone help me to do it!!!

Stop supressing error messages. And try an wrapper class like PHPMailer. Try some other destination address.

Spot the difference:

$email_from1 = $_POST['uname1']; // required

and

$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .

While you’re at it, it’s not a good idea to send emails “from” someone else’s address - a lot of proper SMTP servers will refuse to send emails from a domain they are not configured to handle. Send it from your own email address, and just use reply-to for the customers address.

Your form is confusing - the error message when you leave uname1 empty says “Please enter user name”, the prompt clearly says “Email”, and the field name is uname1. Using consistent names makes things easier.