In the Iron Man movie where do we see Captain shield?

You're likely thinking of Iron Man 2 (2010), not the first Iron Man movie.

Captain America, in the form of a small, frozen, and partially thawed body, is first shown in a post-credits scene at the end of Iron Man 2. This sets the stage for the later Captain America: The First Avenger film.

The first Iron Man movie (2008) doesn't feature Captain America in any form.