note: developed on version 2.3.2, other versions can need some edits - fell free to contribute!

1. Requiring installed vQmod because vQmod doesn't support installing via composer itself.
2. composer require burdapraha/oc_invoice_pdf
3. composer require sasedev/composer-plugin-filecopier for files manipulating
4. Add this code to your composer.json project file, extra section:

    "extra": {
        "filescopier": [
            {
                "source": "vendor/burdapraha/oc_invoice_pdf/upload",
                "destination": "upload",
                "debug": "true"
            }
        ]
    }    

It will move vQmod xml file to correct folder.

5. add constant to your config.php & admin/config.php for storage PDF files: For example: define('INVOICES_DIR', DIR_IMAGE . '/invoices'); and fix this folder for reading from web by .htaccess
6. optionally you can add row to your .gitignore file with path to invoice_pdf.xml (example: upload/vqmod/xml/invoice_pdf.xml)
7. celebrate!

• using dompdf to printing
• inspired by Invoice to PDF
• hawkey for talking about solution