POST Value not Being Retrieved AJAX/JQUERY

Question

Why does my Ajax/jQuery not get the POST value of my input type text in my php file. I always keep getting an error of Undefined index: c_post, I tried looking for solution and even trying to fix it myself but nothing is working and its almost a day. Here is my HTML code. the only thing its inserting in the database and able to Retrieve is the input type="file".

<form method="POST" enctype="multipart/form-data">

  <input type="text" id="c_post" name="c_post" value="Originals" class="form-control">

  <span style="font-weight: bold;">Select Category<span style="color:red;">*</span></span><br>
  <div id="hideme">
    <span style="font-weight: bold;">Select Image Files <span style="color:red;">*</span></span><br>
    <input type="file" name="multiple_files" id="multiple_files" multiple /><br>
    <span class="text-muted">Only .jpg, png, .gif file allowed</span>
    <span id="error_multiple_files"></span>
  </div>

</form>

Here is my Ajax

$.ajax({
  url: "upload.php",
  method: "POST",
  data: form_data,
  contentType: false,
  cache: false,
  processData: false,
  beforeSend: function() {
    $('#error_multiple_files').html('<br /><label class="text-primary">Uploading...</label>');
  },
  success: function(data) {
    $('#error_multiple_files').html('<br /><label class="text-success">Uploaded</label>');
    load_image_data();
  }
});

data: form_data is my
var form_data = new FormData();

Upload.php

//upload.php

include('database_connection.php');
// include_once '../assets/conn/dbconnect.php';
// $radioVal = $_POST["MyRadio"];
// $req = $_REQUEST['test'];

// $inquery = mysqli_query($con,"INSERT into tbl_image (category) VALUES ('$radioVal')");


if(count($_FILES["file"]["name"]) > 0)
{
 //$output = '';
 sleep(3);
 for($count=0; $count<count($_FILES["file"]["name"]); $count++)
 {


  $c_post = $_POST['c_post'];
  $file_name = $_FILES["file"]["name"][$count];
  $tmp_name = $_FILES["file"]['tmp_name'][$count];
  $file_array = explode(".", $file_name);
  $file_extension = end($file_array);
  $mtrand = mt_rand(1, 5000);
  if(file_already_uploaded($file_name, $connect))
  {
   $file_name = $file_array[0] . '-'. rand() . '.' . $file_extension;
  }
  $location = 'files/' . $file_name;
  if(move_uploaded_file($tmp_name, $location))
  {
   $query = "
   INSERT INTO tbl_image (image_name, image_description, category) 
   VALUES ('$file_name', '$mtrand', '$c_post')
   ";
   $statement = $connect->prepare($query);
   $statement->execute();
  }
 }
}

function file_already_uploaded($file_name, $connect)
{

 $query = "SELECT * FROM tbl_image WHERE image_name = '".$file_name."'";
 $statement = $connect->prepare($query);
 $statement->execute();
 $number_of_rows = $statement->rowCount();
 if($number_of_rows > 0)
 {
  return true;
 }
 else
 {
  return false;
 }
}

?>

I just want to add a category and I am not sure why even a simple post won't just let me allow it to happen

This was the project I am trying to make and trying to make different changes to fit my preference