To update a bibliography field that is not contained in a right-click the bibliography, and then click update field on the shortcut menu.

The answer to this question is Style.

Explanation:

This updates a bibliography:-

1.Click the bibliography. A frame pops up around it.

2.Click on the arrow present on the frame, and then click on Update.

But if we have to update a bibliography field and it is not within a style,right click on the bibliography after that click Update field on the shortcut menu.