PHP - Php Html Email Contact Form Problem.

I really need some help.  I am very new to PHP and I've been stuck for a couple of days.  I created a contact form and everything seems to be working correctly, except the mail is showing it's sent, but I never receive an email in my Inbox or Spam folder.  Can someone please review my code?

Here is the PHP:

<?php
  // DEFINE VARIABLE AND SET EMPTY VALUES
  $varfnameErr = $varlnameErr = $varemailErr = $varphoneErr = $varpositionErr = "";
  $varfname = $varlname = $varemail = $varphone = $varposition = $success = "";

  
  //FORM SUBMITTED WITH POST METHOD
  if ($_SERVER["REQUEST_METHOD"] == "POST") {

    //VALIDATE FIRST NAME
    if (empty($_POST["varfname"])) {
      $varfnameErr = "First Name is required";
    } else {
      $varfname = test_input($_POST["varfname"]);
      // MAKE SURE FIRST NAME ONLY CONTAINS LETTERS AND WHITE SPACE
      if (!preg_match("/^[a-zA-Z ]*$/",$varfname)) {
        $varfnameErr = "Only letters and white space are allowed";
      }
    }

    //VALIDATE LAST NAME
    if (empty($_POST["varlname"])) {
      $varlnameErr = "Last Name is required";
    } else {
      $varlname = test_input($_POST["varlname"]);
      // MAKE SURE LAST NAME ONLY CONTAINS LETTERS AND WHITE SPACE
      if (!preg_match("/^[a-zA-Z ]*$/",$varlname)) {
        $varlnameErr = "Only letters and white space are allowed";
      }
    }
  
    //VALIDATE EMAIL ADDRESS
    if (empty($_POST["varemail"])) {
      $varemailErr = "Email Address is required";
    } else {
      $varemail = test_input($_POST["varemail"]);
      // MAKE SURE EMAIL ADDRESS IS FORMATTED CORRECTLY
      if (!filter_var($varemail, FILTER_VALIDATE_EMAIL)) {
        $varemailErr = "Invalid email address format";
      }
    }

    //VALIDATE PHONE NUMBER
    if (empty($_POST["varphone"])) {
      $varphoneErr = "Phone number is required";
    } else {
      $varphone = test_input($_POST["varphone"]);
      // MAKE SURE PHONE NUMBER IS IN CORRECT FORMAT
      if (!preg_match("/^(\d[\s-]?)?[\(\[\s-]{0,2}?\d{3}[\)\]\s-]{0,2}?\d{3}[\s-]?\d{4}$/i",$varphone)) {
        $varphoneErr = "Invalid telephone format";
      }
    }
	
    //VALIDATE POSITION
    if (empty($_POST["varposition"])) {
      $varpositionErr = "Position is required";
    } else {
      $varposition = test_input($_POST["varposition"]);
    }

    //IF ALL DATA IS CORRECT
    if ($varfnameErr == '' and $varlnameErr == '' and $varemailErr == '' and $varphoneErr == '' and $varpositionErr == '') {
      $message_body = '';
      unset($_POST['submit']);

      //THIS IS JUST FOR TESTING PURPOSES
      $message_body = $varfname;

      //foreach ($_POST as $key => $value) {
      //    $message_body .= "$key: $value\n";
      //}
      $to = 'mygmail@gmail.com';
      $subject = 'Volunteer Form Submission';
      
      $message = wordwrap($message_body, 70);
      $headers  = 'MIME-Version: 1.0' . "\r\n"; 
      $headers .= 'Content-type: text/html; charset=utf-8' . "\r\n";
      $headers .= "From: " . $varemail . "\r\n";
      $subject = 'Volunteer Form Submission';
      $to = 'mygmail@gmail.com';
      $result = mail($to, $subject, $message, $headers);
      //THIS RETURNS "1"
      print $result;
      
      //IF ALL DATA IS CORRECT MAKE SURE EMAIL WAS SENT
      if (mail($to, $subject, $message, $headers)) {
        $success = "Message sent. Thank you contacting us! We will reply as soon as possible.";
        $varfname = $varlname = $varemail = $varphone = $varposition = "";
      } else {
        $success = "Something went wrong!";
      }
    }
  }

//STRIP UNWANTED CHARACTERS FROM VARIABLES
function test_input($data) {
  $data = trim($data);
  $data = stripslashes($data);
  $data = htmlspecialchars($data);
  return $data;
}
?>

Here is the HTML:

    <div class="row regformrow">
      <div class="coffee-span-12 regformcolumn">
        <div class="subgrid regformsubgrid">
          <div class="row regformsubgridheaderrow">
            <div class="coffee-span-12 regformsubgridheadercolumn">
              <h4 class="regformsubgridheadertitle">Volunteer Form</h4>
            </div>
          </div>
          <div class="row regformsubgridrow">
            <form class="form-container regformsubgridformcontainer" action=<?= $_SERVER['PHP_SELF']; ?> method="post">
              <div class="coffee-span-4 coffee-972-span-6 coffee-458-span-12 regformsubgridcolumn1">
                <div class="container regformsubgridcontainer1">
                  <label class="label form-label-all"><span style="font-style:italic;color:#FF5454;">* Required Fields</span></label></br>
                  <div class="formfieldgroup">
                    <input class="fname" name="varfname" type="text" tabindex="1" placeholder="First Name" value="<?= $varfname; ?>"><span class="requiredfield"> *</span>
                    <span class="form-error"><?= $varfnameErr ?></span>
                  </div>
                  <div class="formfieldgroup">
                    <input class="lname" name="varlname" type="text" tabindex="2" placeholder="Last Name" value="<?= $varlname; ?>"><span class="requiredfield"> *</span>
                    <span class="form-error"><?= $varlnameErr ?></span>
                  </div>
                  <div class="formfieldgroup">
                    <input class="email" name="varemail" type="text" tabindex="2" placeholder="Email Address" value="<?= $varemail; ?>"><span class="requiredfield"> *</span>
                    <span class="form-error"><?= $varemailErr ?></span>
                  </div>
                  <div class="formfieldgroup">
                    <input class="phone" name="varphone" type="text" tabindex="2" placeholder="Telephone Number" value="<?= $varphone; ?>"><span class="requiredfield"> *</span>
                    <span class="form-error"><?= $varphoneErr ?></span>
                  </div>
                  <div class="formfieldgroup">
                    <select class="select selectbox" name="varposition" id="varposition" tabindex="5"><option value="">Select one...</option><option value="Chaperone">Chaperone</option><option value="Class Monitor">Class Monitor</option><option value="Parking Attendant">Parking Attendant</option><option value="Party Coordinator">Party Coordinator</option><option value="Teacher Aid">Teacher Aid</option></select><span class="requiredfield"> *</span>
                    <span class="form-error"><?= $varpositionErr ?></span>
                  </div>
                  <div class="formfieldgroup">
                    <input class="test" name="test" type="text" tabindex="6" placeholder="If you are human, leave this field blank" value="">
                  </div>
                  <div class="formfieldgroup">
                    <button type="submit" class="button-submit-1" name="submit" tabindex="7" data-submit="...Sendng">Submit</button>
                  </div>
                  <div class="formfieldgroup">
  				  <div class="success"><?= $success; ?></div>
                  </div>
                </div>
              </div>
            </form>
          </div>
        </div>
      </div>
    </div>

I have a one-page responsive website template with a built-in contact email form whereby I would like to add an upload file attachment provision to the contact form. While I have been able to successfully add two fields (source, URL) to the built-in contact email form, with exception of adding the HTML to the form , modification to the contact email form's PHP files  appears to be much more involved whereby I have been unable to find a barebones PHP code I can add to the existing PHP to make this work. I should also add that while I am well versed in HTML, CSS, and Javascript, I am not when it comes to PHP. In brief, I prefer not to replace the built-in contact form with different HTML and PHP for adding a contact form email file attachment.  Any suggestions regarding this subject matter are appreciated. Since PHP is not listed under accepted file types for attachment to this post, I can provide download links to the contact email form PHP files from my iHost server for review if need be. The website address to view the HTML source code for the built-in contact form is https://www.seoauditspecialists.com. Apart from my having to add 'enctype=”multipart/form-data”' to the contact form's <form action> line of code, the HTML to add the 'file' field is provided below. Thank you ahead of time.

              <div class="form-group">
                <input type="file" class="form-control" name="uploaded_file" id="uploaded_file" /
              </div>

Hi I built a really simple customer review form https://kickasssoftwear.uk/dev/reviews.html (it's only been optimised for mobile view so far) and it works using the php mail script on this page https://kickasssoftwear.uk/dev/empty2.php - the emails are being sent to me and the format of the emails is OK, and the form redirects to the empty2 page with a mailsent message in the address bar.

I know I can leave that page as is and write a nice thank you message in the html - but what I really want to do is have the customers name there too, Thanks 'name' your review has been sent,

but I can't get it to work - it's been 4 whole days now and I really need to eat & sleep! Please if anyone has suggestions or advice for a noob, please help. Thanks