n8n Invoice Automation: JS + Google Sheets PDF, Drive & Email

Turn form submissions into branded PDF invoices—automatically

This n8n invoice automation workflow takes each new order form submission, generates a unique invoice/order ID, creates a PDF invoice, stores it in your cloud, emails it to the customer, and logs all invoice data in Google Sheets—end to end.

What this workflow does

• Webhook Trigger: Starts when an order form is submitted, capturing customer and order details.
• Generate a unique Order ID: A Function/Code step creates a random alphanumeric ID (example: INV-X92B7D).
• Duplicate prevention with Google Sheets: The workflow checks your invoice log sheet for the generated ID. If a duplicate is found, it regenerates the ID and loops until the ID is unique.
• Prepare invoice data: A Set step formats customer info, order items, date, and the unique order ID for your invoice template.
• Convert HTML to PDF: An HTTP Request node sends the invoice HTML to a RapidAPI HTML-to-PDF service and receives the PDF.
• Upload to Drive (or Dropbox): The PDF is saved to Google Drive or Dropbox with a clear filename like Invoice-INV-X92B7D.pdf.
• Email the invoice: An Email Send node attaches the PDF and includes the order ID in the email subject/body.
• Log the invoice: The workflow appends customer info, order ID, total, and the PDF link to your Google Sheet for tracking.

Use cases

• Small SaaS or service businesses that receive orders via web forms and need automatic invoice PDFs.
• Teams that want reliable invoice tracking with unique IDs and a Google Sheets audit log.
• Operations workflows that require sending invoices immediately after checkout without manual work.

Technical details

• n8n nodes: Webhook, Code/Function, IF, Set, HTTP Request, Email Send, and a PDF upload step for Google Drive or Dropbox (plus supporting nodes like Sticky Notes for clarity).
• Data store: Google Sheets invoice log (duplicate ID checks + invoice logging).
• PDF generation: RapidAPI HTML-to-PDF via HTTP Request.