How To Write A Business Letter With Unknown Recipient . A typical heading for a business letter includes: Addressing a business letter starts with an appropriate heading at the top left side of the page, followed by a professional salutation. How To Address A Letter To Unknown Recipient Sample Letter Of from plastikbekass.blogspot.com However, if you are sending out a cover letter to an unknown hiring influence, you can address it. Also, if the letter isn't about business, for example you are inviting the claims adjustor to a party, you would use a comma: Such a letter is known as ‘to whom it.