How to update image with PHP and AJAX?

Question

Im trying to update user image with php but im facing errors that $_FILES is not defined. Already is set but facing the same issue. I have tried to find in other answers here but its not working.
File path is added on database without extension (example: photos/5f583778a818e.) but file is not moved to directory (folder). I appreciate your help!

Image Directory: dms>views>photos

public function updateuser(){
      GLOBAL $conn;
        if(@$_POST['first'] && (@$_POST['last']) && (@$_POST['filepath']) && !empty($_POST['filepath'])){
        //if(@$_POST['first'] && (@$_POST['last']) && (@$_POST['filepath']){
        //}


            if($_SESSION['id']){
                $id = $_SESSION['id'];
            }
            $user = new UserModel();
            //echo $id;
            $user->first = trim($_POST['first']);
            $user->last = trim($_POST['last']);
            @$filetemp = isset($_FILES['filepath']['tmp_name']);
            @$filename = uniqid(isset($_FILES['filepath']['name']));
            @$filetype = end(explode('.', ($_FILES['filepath']['name'])));
            $filename = $filename . '.' . $filetype;
            $user->filepath = "photos/" . $filename;
            move_uploaded_file($filetemp, $user->filepath);
            //var_dump($_FILES);
            //var_dump(is_dir('photos/')); check if folder is DIR
           
            $query = $conn->prepare("UPDATE users SET first = ?, last = ?, filepath = ?  WHERE id = '$id'");
            $query->bindValue(1, $user->first);
            $query->bindValue(2, $user->last);
            $query->bindValue(3, $user->filepath);
            $query->execute();
             //print_r($_FILES);
            echo "Updated";
          }else{
              echo "None";
          }

        }

Below is my html

 <form method="POST" enctype="multipart/form-data">
        <div class="main-img-user profile-user input--file"><img id="previewImg"
            src="views/<?php echo $user->filepath; ?>" alt="user-img"
              class="rounded-circle mCS_img_loaded"><a href="JavaScript:void(0);"
              class="fas fa-camera profile-edit"></a>
            <input id="filepath" name="filepath" type="file" onchange="previewFile(this);" />                                       
        </div>
        <input type="submit" id="update" value="Update"  class="btn btn-primary waves-effect waves- 
        light"> 
        <h3 class="result" style="color:green;"></h3>
    </form>

And my AJAX

 $(document).ready(function () {
      $('#update').click(function (e) {
        e.preventDefault(); $.get('/myurl/')
        
        var first = $('#first').val()
        var last = $('#last').val()
     // var password = $('#password').val()
      var filepath = $('#filepath').val()
        
        $.ajax({
          url: 'profile/updateuser',
          method: 'POST',
          data: {
            first: first,
              last: last,
                filepath: filepath
          },
          success: function (data, textStatus) {
            $('.result').html(data).show().delay(6000).fadeOut(300)
          }
        })
      })
    })