Since groff
provides such low-level facilities, it can be quite
difficult to use by itself. However, groff
provides a
macro facility to specify how certain routine operations, such as
starting paragraphs, or printing headers and footers, should be done.
These macros can be collected together into a macro package.
There are a number of macro packages available; the most common (and the
ones described in this manual) are man, mdoc, me,
ms, and mm.