Typist initials
Typist initials are used to indicate the person who typed the letter. If you typed the letter yourself, omit the typist initials.
If you wish to enclose documents, you can either list all enclosed documents separately or just write the word 'Enclosure' below the signature. 
TEXT D
STANDARD LETTER FORMAT aND STYLES
STYLES
1. BLOCK STYLE
All sections of the letter are flush against the left margin of the page. Each paragraph in the body of the letter begins flush left margin, with a one space line dividing each paragraph.
2. SEMI-BLOCK STYLE
The date, signature, and address heading (if not on preprinted letterhead stationary) are aligned on the right side of the page. All other sections are flush left margin. Paragraphs in the body of the letter begin flush left with a one space line dividing each paragraph.
3. INDENTED STYLE
The date, signature, and address heading (if not on preprinted letterhead stationary) are aligned on the right side of the page. The greeting is flush left. Paragraphs in the body of the letter are indented with no space line between paragraphs. Postscript and notations are flush left.
4. MEMORANDUM STYLE
This is a business format that is best used for interoffice correspondence. Directly above the body of the memorandum, are the following sections flush left:
• “Date:”
• “To:” Name or column of names of those people to whom memorandum is being sent. (listed in alphabetical order by surname).
• “From:” Writer’s name. Title, if any, listed directly below name.
• “Re:” or “Subject:” Subject line may be emphasized by underlining, bold font or all capital letters.
Body text may be indented or block format. Signature of writer not required on Memorandums.