1. Salutations
When to use what

2. The simple rule is that Dear Sir/Madam, Font and Size
is a very good formal start to a letter if you do not know the receiver’s name.

3. Dear Sir/Madam,
However, Dear Sir/Madam is impersonal, and shows you do not know the gender. Dear Mr Smith, would be better, because it shows you know the individual person’s name

4. Salutation/Complimentary Close
If you know the name of the person receiving the letter, end with Yours Sincerely. If you do not know the name, end with Yours Faithfully. Dear Sir/Madam,  Yours Faithfully Dear Mr Finch,  Yours Sincerely