GET EXTENSION

Use modman Linux | Windows :

cd magento_root/
modman clone https://github.com/khoazero123/M2OverrideCreateInvoice.git
modman deploy M2OverrideCreateInvoice

Use git:

git clone https://github.com/khoazero123/M2OverrideCreateInvoice.git
cp -r M2OverrideCreateInvoice/* magento_root/

INSTALLATION

bin/magento setup:upgrade