The standard LaTeX document classes define a small set of `page styles' which (in effect) specify head- and footlines for your document. The set defined is very restricted, but LaTeX is capable of much more; people occasionally set about employing LaTeX facilities to do the job, but that's quite unnecessary - Piet van Oostrum has already done the work.
The package is found in directory macros/latex/contrib/supported/fancyhdr and provides simple mechanisms for defining pretty much every head- or footline variation you could want; the directory also contains some (rather good) documentation and one or two smaller packages. Fancyhdr also deals with the tedious behaviour of the standard styles with initial pages, by enabling you to define different page styles for initial and for body pages.