A formal letter has rules to follow, but they are not difficult. To address a formal letter, you just need to make sure you put your return address and the address of the person you are writing to in the correct places. You also always include a date in a formal letter.
Begin your letter with your name. Your name and return address starts right of the centre of your page (as far right as your name and address will fit.) Some people include their phone number and e-mail address with the street address on a formal letter.
Put the date after skipping two spaces. Make sure to write out the name of the month. Do not use abbreviations or numbers for the month when writing a formal letter.
Leave two blank lines. Write the name and address of the person you are writing to. Make sure to use Mr. or Ms. before the person's name, such as Mr. John Smith or Ms. Sarah Stevens. If the person is a doctor, then you would use Dr.
Write your greeting after skipping another two lines. Use Dear with Mr. or Ms. and the person's last name. Use a comma after your greeting. With these simple rules, you have just learnt how to address a formal letter.
When addressing a formal letter, it is best to use the name of a person instead of To Whom It May Concern. If you don't know the name of the addressee, then try calling the business and asking the receptionist for some information to help you. Make sure you ask for the proper spelling. If you don't know if a woman likes to be called Mrs. or Miss, then use Ms. When in doubt, go with the neutral title.