How to add custom field to wordpress page everytime user uploads new image in WP visual editor?

When an image is uploaded via the media editor the action hook add_attachment is triggered, with the ID of the attachment passed as the parameter. You can get full post data for the attachment using the ID to determine the ID of the post/page the image is attached to (stored in the post_parent property). Example code:

add_action( 'add_attachment', 'GoWP_wpse156258' );
function GoWP_wpse156258( $ID ) {
  $attachment = get_post( $ID );
  $post_id = $attachment->post_parent;
  update_post_meta( $post_id, 'your_meta_key', 'your_meta_value' );
}

Hope that helps!