Hi rudraraju.
If you don’t mind putting the post code information into an already existing column, you can do it very easily : just put the follow line of text in the “Additionnal settings” tab of your contact form.
flamingo_subject: “[your-subject] [your-postcode]”
That will only work form future submission and not the ones that are already saved.
If you need another column, you need to do that with some code by using the manage_flamingo_inbound_posts_columns
and manage_flamingo_inbound_posts_custom_column
manage_flamingo_inbound_posts_custom_column filters