English version comes after Japanese.
英語に訳しづらい日本語の1つに｢〇〇さんによろしく｣というのがあると思いますが、｢Please say hello to 〇〇｣というのは割と気軽に言いますね。あとは「Send my regards to 〇〇」というのもありますが、フォーマルな感じになりますね。
"Say hello to 〇〇〇" can be translated into Japanese as "〇〇〇 ni Yoroshiku". "Yoroshiku" is one of the convenient words in Japanese language. It could be used at many occasions as a greeting that doesn't really mean anything by itself.