Many Infoboxes can take another template, including another infobox, as a module (or child-, or sub-template).
Inversely, some infoboxes can have other templates, and other templates, are configured so that they may be embedded as a "child" or "module" infobox within another.
When embedding a template it is usually necessary to set |embed=yes (or |child=yes) in the embedded (child) template.
The child template is entered as the value of a parameter in the parent, usually |module= or |embedded=.