Never do anything directly on a live store. First setup and test on a development domain (i.e. “dev.url.com”).
Temporarily disable Magento cache
To avoid any possible issues with the installation we recommend disabling Magento cache before proceeding with the installation and re-enabling it once the install is complete.
Unzip the extension zip file and upload all files and folders of Backend, Number and Invoice extension to the root folder of your Magento installation.
For how to enable magento 2 module follow this link.
Go to “AGILECODEX->Custom Order Number->Settings
Go to “AGILECODEX-> Invoice Plus ->Settings
Go to “AGILECODEX -> PDF Templates -> Manage PDF Templates
Go to “SALES -> Orders -> View
For create new invoice go to order details page where you can see 4 button for invoice named "Invoice", "Invoice 2", "Invoice 3" and "Invoice 4". The button label "Invoice 2", "Invoice 3" and "Invoice 4" can changeable from configuration as discuss above.
Now you can create an invoice from "Invoice" or "Invoice 2" or "Invoice 3" or "Invoice 4". If you choose "Invoice 2" button then it will create invoice with prefix number like: INV2-19-12-04-00000002 as per as saved configuration.
After create invoice, email will send to the customer with your selected email template.
Go to “SALES -> Invoices -> View -> Print
Thank you for reading this user manual! We'd be glad to help you if you have any question relating to this extension.