Refers to the person to whom a letter, package, email, or other communication is addressed. Often used in formal or postal contexts.
The addressee of this letter is Mr. Tanaka.
The mail was returned because the addressee was unknown.
受取人 is a more general term for 'recipient' of goods or money, while 受信人 is specifically for communications.
Compound of 受信 (jushin, 'reception of a communication') + 人 (nin, 'person').