How to add plugin custom field to custom post type?

Suresh
what is the custom post type you want to hook into?
You need to make sure you change the $custom_post_type=”put-post-type-here”; line to be the actual custom post type slug you want to hook it into. Then, I would suggest adding the function to the functions.php.
And try it this way:

add_action('admin_menu','new_appip_custom_post_type_metabox');
function new_appip_custom_post_type_metabox(){
     if(function_exists('amazonProductInAPostBox1') && function_exists( 'add_meta_box')){
         add_meta_box( 'amazonProductInAPostBox1','Amazon Product In a Post Settings', 'amazonProductInAPostBox1', 'put-post-type-here', 'normal', 'high' );
     }
     return;
}