certified mail
noun🔊/ˌsɜːtɪfaɪd ˈmeɪl/
🔊/ˌsɜːrtɪfaɪd ˈmeɪl/
(North American English) (British English recorded delivery)
[uncountable]a method of sending a letter or package in which the person sending it gets an official note to say it has been posted and the person receiving it must sign a form when it is delivered 挂号邮寄（寄件人会收到发件通知，收件人需签收）