You can easily auto-fill addresses by simply incorporating the yuban-jp plugin into html written in YubinBango specifications.
There are two modules available.
1.zipaddrx.js series
2.yubinbango.js
Designers can choose and use it according to their preference.
For detailed information about yuban-jp, please refer to https://zipaddr2.com/yuban-jp/.
Only the Japanese version is supported.

In Japanese:

郵便番号から住所自動入力を簡単に利用する為のWordpressプラグインです。
YubinBango仕様で記述されたhtmlにプラグインyuban-jpを組み込むだけで動きます。
実働モジュールは次の2系統あります。
1.zipaddrx.js系
2.yubinbango.js
設計者の好みで選択して利用できます。
yuban-jpの詳細説明は、https://zipaddr2.com/yuban-jp/を参照して下さい。
[日本語版のみ対応]

External services

This plugin assists in integration with external tools and automatically inserts script statements into HTML.
The script statements to be inserted are as follows, and can be selected based on the selection in the administration screen.
[Free version]