Writing for a business audience is usually quite different than writing in the humanities, social sciences, or other academic disciplines. Business writing strives to be crisp and succinct rather than evocative or creative; it stresses specificity and accuracy. This distinction does not make business writing superior or inferior to other styles. Rather, it reflects the unique purpose and considerations involved when writing in a business context.
Return address and date: (Upper right hand corner) Once upon a time, this was necessary in case the letter became separated from the envelope, but I doubt that happens much any more. Even so, this is where your reader is going to look to find your address and the date the letter was written, so it should be there. Mailing address of recipient: (Left_hand side, one line below the return address) This identifies the recipient of the letter. In office environments, letters are often removed from their envelopes and circulated; this helps the letter get back to its rightful recipient.