Final answer:
The correct term for the person to whom you are sending a letter is 'addressee' or 'recipient'. Always include both the sender's and recipient's addresses in your letter.
Step-by-step explanation:
The person to whom you are sending a letter is known as the addressee or recipient. When writing a letter, you must include the sender's address and the recipient's address. The sender's address should contain your name, street address, city, state, and zip code. The recipient's address includes the recipient's name, their title if applicable, the company or organization name, and their full address. It is important to use the correct salutation, date format, and ensure the letter or email is properly proofread before sending.