I am trying to add new input field in sales > order > invoice
. This would be like my reference number. This custom input field should be show in sales > order >invoice & sales > invoice
and when I will print the invoice then this custom field need to be get showed. New custom grid need to get added, I am currently working with this Link:
This extension is enable but custom filed is not showing up in admin sales > order
.
Same with this link.
Can some one let me know how I need to proceed for this?