While a simple "Hi," "Hello," or even "Hey" is appropriate in casual correspondence, a more formal salutation is appropriate when you are emailing about a business_related matter, such as a cover letter, letter of recommendation, or inquiry letter.
Parts of Business Letter. A business letter will be more impressive if proper attention is given to each and every part of the business letter. There are 12 Parts of Business Letter. The Heading or Letterhead,Date, Reference, The Inside Address, Subject, Greeting, Body Paragraphs, Complimentary Close, Signature and Writer’s Identification, Enclosures , Copy Circulation, PostScript