Answer to Question 1
In the block letter format, all lines begin at the left margin. This format is efficient because the format is easy to remember, and paragraphs and other letter parts are not indented, which saves keying time.
The modified block style is useful for making a formal, traditional impression. The dateline, complimentary close, and signature block begin at the horizontal center. Paragraphs may or may not be indented.
Answer to Question 2
Letters using mixed punctuation style have a colon after the salutation and a comma after the complimentary close. Letters using open punctuation style omit the colon after the salutation and the comma after the complimentary close.
