In the age of the Internet and large corporations, you sometimes don't know to whom you should address your correspondence. Even corporate or foundation websites aren't always a help; often, the names of the department heads aren't listed, or you can't even find any information at all except a corporate address. However, businesses across the country receive letters each day, even with a mysterious address and no public employee directory.
Look up the company online. Click on the link that says "Contact us;" if this link is not at the top, it is usually along the bottom of the page in the small list of additional links.
Begin the letter by typing your address, without your name. Skip a line, and type the full date.
Find the list of departments or contacts and copy the address. If you cannot find a department address, use the general company address. Paste this address onto your letter.
Type the name of the person and his department above the company's address on the letter, if you know that information. If you don't have a name or department name, take an educated guess at which department you would need. For example, common departments in large companies or foundations include "human resources," "marketing" and "customer relations." Even if you are wrong with the department name, listing the general department will help the receptionist route your letter correctly.
Address the letter to "Dear Mr./Ms. (Last Name):" if you know the recipient's name, or "Dear Sir or Madam:" if you don't know the name of the appropriate department head. Never write "To whom it may concern:" because that sounds unprofessional.
Complete the rest of the letter.
Copy the entire corporate address with the department and employee's name, if applicable, onto the envelope.