“Call” post information from “post_id”

So I have custom posts by various users.

Each post has following meta keys:

post_width, post_height along with usual data such as title, description etc as shown below:

$tags = $_POST['post_tags'];
$custom_field_1 = $_POST['custom_1'];
$custom_field_2 = $_POST['custom_2']; 

$post = array(
    'post_title'    => $title,
    'post_content'  => $description,
    'post_category' => $_POST['cat'], 
    'tags_input'    => $tags,                                   
    'post_status'   => 'publish',           
    'post_type' => $_POST['post_type']  
    );                              
$pid = wp_insert_post($post);
add_post_meta($pid, 'post_width', $custom_field_1, true);
add_post_meta($pid, 'post_height', $custom_field_2, true);  

Now when these posts are displayed in a loop, they each get post_id by $id = get_the_ID();

Now the fun part

Now, let say there are 5 posts displayed and each has unique post_id as shown below in the data-post_id in a button.

 <?php echo '<button type="button" class="contact_button" data-post_id="' .$id. '">' ;?>
    Open the contact form
 <?php echo '</button>';?>

When the button is clicked, then a below contact form will be shown :

 <form action="<?php the_permalink(); ?>" method="post">
      <p><label for="name">Name: <span>*</span> <br><input type="text" name="message_name" value="<?php echo esc_attr($_POST['message_name']); ?>"></label></p>
      <p><label for="message_email">Email: <span>*</span> <br><input type="text" name="message_email" value="<?php echo esc_attr($_POST['message_email']); ?>"></label></p>
      <p><label for="message_text">Message: <span>*</span> <br><textarea type="text" name="message_text"><?php echo esc_textarea($_POST['message_text']); ?></textarea></label></p>
      <p><label for="message_human">Human Verification: <span>*</span> <br><input type="text" style="width: 60px;" name="message_human"> + 3 = 5</label></p>
      <input type="hidden" name="submitted" value="1">
         <p><input type="submit"></p>
  </form>

As you can see, the contact form is nothing fancy.

Here is what I am trying to achieve

Since there are 5 posts, I want to make it very specific to each post when the contact form is sent.

Here is what I mean.

Let say there are 5 posts as shown below:

Post # 1:

• Title: What a day
• Post Author: Mike
• Post author’s Email: mike@example.com
• Post descript: It is a sunny day
• Width: 14px
• Height: 15px
• Contact Button

Post # 2:

• Title: This is a post 2
• Post Author: Steve
• Post author’s Email: steve@example.com
• Post descript: It is Sunday
• Width: 1222px
• Height: 1233px
• Contact Button

etc.

Now, each post has contact button and when the button is clicked and contact form is shown, I want to automatically have these post meta to be filled in (of course hidden from view). So that when the form is submitted, it will have post information and be able to tell which post the viewer contacted from.

I hope I am making sense.

So, here is my question.

How do I call or save post meta (such as title, description, custom meta, etc) based on the post_id of each post? (since each button will have unique post_id, that will be a good starting point to call the rest of the data)

Any help will be much appreciated.

Thanks!

Update 1:

So, I have the contact form in a contact.php which is called via ajax.

The reason why I am using the ajax to call the contact form is to save the bandwidth. Here is a scenario. Let say there are 50 posts on a single page. Then if the contact form is generated for all the posts, then that will severely increase the total page size.

In order to avoid it, I am implementing ajax to call the contact form only when the button is clicked.

So, here is a question.

How do I “pass” the post_id to another php file? (contact_form.php) so that the contact form will be unique?

Thanks!