Where does a post script appear in a business letter?

In a single-spaced letter, type the postscript two lines below whatever was typed last, which will usually mean that the PS appears after your name.

Yours truly,

George Spelvin

P.S. This example shows the location and the spacing of a postscript.

A postscript can be used effectively to express an idea that has been deliberately withheld from the letter so that it can be given a prominent place, with greater emphasis, in the P.S.

However, if the postscript is used merely to express an afterthought, it is usually better to recast the letter so that the idea has its proper place in the body of the letter. Afterthoughts in a postscript give readers the impression that the letter is poorly organized and that the writer did not consider the ideas and their relationships carefully; when an afterthought it tacked on, that impression is often correct.