itemless-invoice

composer config repositories.invoice vcs https://github.com/TomashKhamlai/itemless-invoice
composer require tomashkhamlai/itemless-invoice "dev-master"

OR

mkdir -p app/code/Itemless/Invoice
git clone https://github.com/TomashKhamlai/itemless-invoice app/code/Itemless/Invoice

AND

php bin/magento setup:upgrade