Advoca, I notice that you’ve answered my question in another post. A good guide to American style business letters is "Merriam Webster's Guide to Business Correspondence." It comes with a disk with sample letters too. It is published by

There is no hard and fast rule, but the most common practice is to put the author's initials in capitals and the typist's initials in lower case. Here is an example: LC/vb When there are more pages than one in a letter it is normal practice

I believe u can find some sample letters for the same purpose in immigration website.