WordPress: ウェブサイト全体の非公開 https://www.ivy-web.com/blog/wordpress-private/ https://kinsta.com/jp/blog/password-protect-wordpress-site/
WordPress: 必要なプラグイン https://qiita.com/transel/items/270583ff2dcec64f787f https://webst8.com/blog/wordpress-recommend-plugin-lists/