.H n [heading]Print a numbered heading at level n, where n is from 1 to 7.
See any of the following for more information:
Page eject.
Break after heading.
Centered heading.
Type of first paragraph after heading.
Space after heading.
Unnumbered headings.
Font control.
Point size.
Heading mark.
Unnumbered headings.
User-supplied macros invoked during output of header.