Generate PDF invoices from a Docs template

Step 1: the template

Create a Google Doc called Invoice Template and design it as you like (logo, address, table). Wherever data should go, type a placeholder in double curly braces:

INVOICE {{InvoiceNo}}                     Date: {{Date}}

Bill to: {{Customer}}
Phone:   {{Phone}}

Item: {{Item}}
Amount: ₹{{Amount}}
GST:    ₹{{Gst}}
Total:  ₹{{Total}}

Copy the Doc's ID from its URL: docs.google.com/document/d/<TEMPLATE_ID>/edit.

Step 2: the sheet

Tab Invoices:

Step 3: the script

const TEMPLATE_ID = 'PASTE_TEMPLATE_DOC_ID';
const OUTPUT_FOLDER_ID = 'PASTE_FOLDER_ID';
const GST_RATE = 0.03;

function createInvoices() {
  const sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Invoices');
  const lastRow = sheet.getLastRow();
  if (lastRow < 2) return;

  const rows = sheet.getRange(2, 1, lastRow - 1, 8).getValues();
  const folder = DriveApp.getFolderById(OUTPUT_FOLDER_ID);
  const tz = Session.getScriptTimeZone();

  rows.forEach((r, i) => {
    const [invoiceNo, date, customer, phone, email, item, amount, link] = r;
    if (!invoiceNo || link) return; // skip blank rows and rows already done

    const gst = Math.round(amount * GST_RATE * 100) / 100;
    const total = amount + gst;
    const fmt = n => Number(n).toLocaleString('en-IN', { minimumFractionDigits: 2 });

    // 1. Copy the template
    const copy = DriveApp.getFileById(TEMPLATE_ID).makeCopy(`Invoice ${invoiceNo}`, folder);

    // 2. Replace placeholders
    const doc = DocumentApp.openById(copy.getId());
    const body = doc.getBody();
    const values = {
      InvoiceNo: invoiceNo,
      Date: Utilities.formatDate(new Date(date), tz, 'dd-MMM-yyyy'),
      Customer: customer,
      Phone: phone,
      Item: item,
      Amount: fmt(amount),
      Gst: fmt(gst),
      Total: fmt(total)
    };
    Object.entries(values).forEach(([key, val]) => {
      body.replaceText(`\\{\\{${key}\\}\\}`, String(val));
    });
    doc.saveAndClose();

    // 3. Export as PDF and remove the temporary Doc
    const pdf = folder.createFile(copy.getAs(MimeType.PDF)).setName(`Invoice ${invoiceNo}.pdf`);
    copy.setTrashed(true);

    // 4. Save the link back to the sheet
    sheet.getRange(i + 2, 8).setValue(pdf.getUrl());

    // 5. Email it (optional)
    if (email) {
      GmailApp.sendEmail(email, `Invoice ${invoiceNo}`,
        `Dear ${customer},\n\nPlease find your invoice attached.\n\nThank you.`,
        { attachments: [pdf.getBlob()], name: 'Accounts Team' });
    }
  });
}

Why each step matters

• makeCopy — never edit the template itself; always work on a copy.
• replaceText uses a regular expression. Curly braces have special meaning there, so we escape them: \\{\\{Date\\}\\}. Without escaping, some placeholders won't be found.
• saveAndClose() — must be called before export, or the PDF may show the old placeholders.
• getAs(MimeType.PDF) — converts the Doc to a PDF blob; createFile saves it.
• setTrashed(true) — moves the temporary Doc to the bin so your folder only has PDFs.
• The link column doubles as a "done" marker, so re-running only creates new invoices.

Variations

• Use a Google Slides template for designs with images (SlidesApp, replaceAllText).
• Combine with the year/month folder helper from the Drive lesson.
• Run it from a menu item, or from a form-submit trigger to invoice each new order automatically.

Key points

• Template + placeholders + copy + replace + export = automated documents.
• Escape { and } in replaceText patterns.
• Store the PDF link to avoid creating duplicates.