Setting up invoicing for 1C-Bitrix payments

Invoice Issuance Setup in 1C-Bitrix

An invoice is a document issued to a buyer (individual or legal entity) that contains payment details. In the B2B segment this is a mandatory step: the counterparty's accounting department must receive the invoice, approve it, and pay by bank transfer. In Bitrix, invoice issuance is a separate piece of functionality that can be implemented via the CRM module (Bitrix24), via custom site components, or through 1C integration.

Invoice from the Order Admin Page

The simplest option — generating an invoice based on an existing order. Add an "Issue Invoice" button to the order card:

// /bitrix/admin/sale_order_invoice.php
require_once $_SERVER['DOCUMENT_ROOT'] . '/bitrix/modules/main/include/prolog_admin_before.php';
\Bitrix\Main\Loader::includeModule('sale');

$orderId = (int)$_GET['ORDER_ID'];
$order   = \Bitrix\Sale\Order::load($orderId);

if ($_POST['generate']) {
    $generator = new InvoiceGenerator();
    $pdfPath   = $generator->generate($order);

    // Send email with PDF
    $mailer = new InvoiceMailer();
    $mailer->send($order, $pdfPath);

    // Save the invoice issuance fact to the order property
    $order->setField('INVOICE_DATE', date('d.m.Y'));
    $order->setField('INVOICE_NUMBER', generateInvoiceNumber($orderId));
    $order->save();

    LocalRedirect('/bitrix/admin/sale_order_detail.php?ID=' . $orderId . '&lang=ru');
}

Invoice Structure: Required Fields

According to accounting requirements, an invoice must contain:

• Number and issue date
• Seller details: name, Tax ID (INN/KPP), bank, current account, BIC
• Buyer details: name, Tax ID (INN/KPP), address
• List of goods/services with quantity, unit price, and total
• VAT (if applicable): rate and amount
• Total amount in words
• Signatures of the director and chief accountant

PDF Invoice Generation

use Mpdf\Mpdf;

class InvoiceGenerator
{
    private array $sellerDetails;

    public function __construct()
    {
        $this->sellerDetails = [
            'name'         => 'LLC "My Store"',
            'inn'          => '7701234567',
            'kpp'          => '770101001',
            'address'      => '115093, Moscow, Primernaya St., 1',
            'bank'         => 'Sberbank PJSC',
            'bik'          => '044525225',
            'account'      => '40702810938000000001',
            'corr_account' => '30101810400000000225',
            'director'     => 'I.I. Ivanov',
            'accountant'   => 'A.A. Petrova',
        ];
    }

    public function generate(\Bitrix\Sale\Order $order, string $invoiceNumber): string
    {
        $mpdf = new Mpdf([
            'format'      => 'A4',
            'orientation' => 'P',
            'margin_top'  => 15,
            'margin_left' => 20,
            'margin_right'=> 15,
        ]);
        $mpdf->SetFont('dejavusans');

        $buyer  = $this->getBuyerDetails($order);
        $items  = $this->getOrderItems($order);
        $totals = $this->calculateTotals($items);

        $html = $this->renderInvoiceHtml([
            'number'   => $invoiceNumber,
            'date'     => date('d.m.Y'),
            'seller'   => $this->sellerDetails,
            'buyer'    => $buyer,
            'items'    => $items,
            'totals'   => $totals,
            'in_words' => $this->amountInWords($totals['total']),
        ]);

        $mpdf->WriteHTML($html);

        $uploadDir = '/upload/invoices/';
        if (!is_dir($_SERVER['DOCUMENT_ROOT'] . $uploadDir)) {
            mkdir($_SERVER['DOCUMENT_ROOT'] . $uploadDir, 0755, true);
        }

        $filename = 'invoice_' . $order->getId() . '_' . date('Ymd') . '.pdf';
        $fullPath = $_SERVER['DOCUMENT_ROOT'] . $uploadDir . $filename;
        $mpdf->Output($fullPath, 'F');

        return $uploadDir . $filename;
    }

    private function getOrderItems(\Bitrix\Sale\Order $order): array
    {
        $items = [];
        $num   = 1;
        foreach ($order->getBasket()->getOrderableItems() as $item) {
            $price = $item->getBasePrice();
            $qty   = $item->getQuantity();
            $items[] = [
                'num'   => $num++,
                'name'  => $item->getField('NAME'),
                'unit'  => 'pcs.',
                'qty'   => $qty,
                'price' => $price,
                'total' => $price * $qty,
                'vat'   => 0,  // or calculate from the item's VAT rate
            ];
        }
        return $items;
    }
}

Invoice Numbering

The invoice number must be unique. Recommended format: INV-YYYY-NNNN (year + sequence number):

function generateInvoiceNumber(): string
{
    $year    = date('Y');
    $counter = (int)COption::GetOptionInt('my_module', 'invoice_counter_' . $year, 0) + 1;
    COption::SetOptionInt('my_module', 'invoice_counter_' . $year, $counter);
    return 'INV-' . $year . '-' . str_pad($counter, 4, '0', STR_PAD_LEFT);
}

Sending the Invoice by Email

$event = new \Bitrix\Main\Mail\Event([
    'EVENT_NAME'  => 'ORDER_INVOICE',
    'TO_EMAIL'    => $buyerEmail,
    'ATTACHMENTS' => [
        [
            'path' => $_SERVER['DOCUMENT_ROOT'] . $pdfPath,
            'name' => 'Invoice_' . $invoiceNumber . '.pdf',
        ],
    ],
    'FIELDS' => [
        'INVOICE_NUMBER' => $invoiceNumber,
        'ORDER_ID'       => $orderId,
        'BUYER_NAME'     => $buyerName,
        'AMOUNT'         => $totalAmount,
    ],
]);
\Bitrix\Main\Mail\Event::send($event);

Timeline