Title: Kazuki Qualified Invoice Number for WooCommerce
Author: kazukiyamashita80
Published: <strong>June 19, 2026</strong>
Last modified: June 19, 2026

---

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# Kazuki Qualified Invoice Number for WooCommerce

 By [kazukiyamashita80](https://profiles.wordpress.org/kazukiyamashita80/)

[Download](https://downloads.wordpress.org/plugin/kazuki-qualified-invoice-number-for-woocommerce.1.0.5.zip)

 * [Details](https://wordpress.org/plugins/kazuki-qualified-invoice-number-for-woocommerce/#description)
 * [Reviews](https://wordpress.org/plugins/kazuki-qualified-invoice-number-for-woocommerce/#reviews)
 *  [Installation](https://wordpress.org/plugins/kazuki-qualified-invoice-number-for-woocommerce/#installation)
 * [Development](https://wordpress.org/plugins/kazuki-qualified-invoice-number-for-woocommerce/#developers)

 [Support](https://wordpress.org/support/plugin/kazuki-qualified-invoice-number-for-woocommerce/)

## Description

Adds an optional or required field for **適格請求書発行事業者登録番号** on WooCommerce
checkout.

 * Validates format: `T` + 13 digits
 * Works with WooCommerce Checkout Block
 * Stores value on the order
 * Shows in admin order screen and customer emails
 * Settings under WooCommerce  Settings  インボイス登録番号

For registered business verification, use the [NTA invoice public site](https://www.invoice-kohyo.nta.go.jp/).

## Installation

 1. Upload the plugin folder to `/wp-content/plugins/` or install via WordPress plugins
    screen.
 2. Activate through the ‘Plugins’ menu.
 3. Ensure WooCommerce is active.
 4. Configure under WooCommerce  Settings  インボイス登録番号.

## FAQ

### Does this verify registration with the tax office?

No. It validates the number format only. Use the NTA public site for official status.

## Reviews

There are no reviews for this plugin.

## Contributors & Developers

“Kazuki Qualified Invoice Number for WooCommerce” is open source software. The following
people have contributed to this plugin.

Contributors

 *   [ kazukiyamashita80 ](https://profiles.wordpress.org/kazukiyamashita80/)

[Translate “Kazuki Qualified Invoice Number for WooCommerce” into your language.](https://translate.wordpress.org/projects/wp-plugins/kazuki-qualified-invoice-number-for-woocommerce)

### Interested in development?

[Browse the code](https://plugins.trac.wordpress.org/browser/kazuki-qualified-invoice-number-for-woocommerce/),
check out the [SVN repository](https://plugins.svn.wordpress.org/kazuki-qualified-invoice-number-for-woocommerce/),
or subscribe to the [development log](https://plugins.trac.wordpress.org/log/kazuki-qualified-invoice-number-for-woocommerce/)
by [RSS](https://plugins.trac.wordpress.org/log/kazuki-qualified-invoice-number-for-woocommerce/?limit=100&mode=stop_on_copy&format=rss).

## Changelog

#### 1.0.5

 * readme tags fix (no spaces). Final naming for WordPress.org review.

#### 1.0.4

 * Rename plugin for WordPress.org guidelines (Kazuki Qualified Invoice Number for
   WooCommerce).
 * Add Requires Plugins header for WooCommerce.
 * Remove load_plugin_textdomain (WordPress.org language packs).
 * Author: Kazuki Yamashita.

#### 1.0.3

 * WordPress.org plugin check: Tested up to 7.0, text domain, languages folder.

#### 1.0.2

 * Fix checkout completion error on block checkout (email/admin display).
 * Block checkout support via WooCommerce additional checkout fields API.

#### 1.0.1

 * WooCommerce Checkout Block support.

#### 1.0.0

 * Initial release.

## Meta

 *  Version **1.0.5**
 *  Last updated **11 hours ago**
 *  Active installations **Fewer than 10**
 *  WordPress version ** 6.0 or higher **
 *  Tested up to **7.0**
 *  PHP version ** 7.4 or higher **
 * Tags
 * [checkout](https://wordpress.org/plugins/tags/checkout/)[invoice](https://wordpress.org/plugins/tags/invoice/)
   [japan](https://wordpress.org/plugins/tags/japan/)[woocommerce](https://wordpress.org/plugins/tags/woocommerce/)
 *  [Advanced View](https://wordpress.org/plugins/kazuki-qualified-invoice-number-for-woocommerce/advanced/)

## Ratings

No reviews have been submitted yet.

[Your review](https://wordpress.org/support/plugin/kazuki-qualified-invoice-number-for-woocommerce/reviews/#new-post)

[See all reviews](https://wordpress.org/support/plugin/kazuki-qualified-invoice-number-for-woocommerce/reviews/)

## Contributors

 *   [ kazukiyamashita80 ](https://profiles.wordpress.org/kazukiyamashita80/)

## Support

Got something to say? Need help?

 [View support forum](https://wordpress.org/support/plugin/kazuki-qualified-invoice-number-for-woocommerce/)