customise the invoice save option

Question

I want to allow the invoice save action once the order is in processing state for this i have to add some logics inside the Magento\Sales\Controller\Adminhtml\Order\Invoice save file. please advice me

Answer 1

etc/di.xml

create a file for this xx\yy\Controller\Adminhtml\Order\Invoice\Save.php inside the save.php file write your own logic.