Penis enlargement is any technique for enlarging the penis.
There are various surgical methods. One is beading, where small objects are implanted under the skin of the penis, usually close to the glans.
A do-it-yourself method is a penis pump; this is dubious as an enlargement technique though it can be an effective masturbation aid. "Penis enlargement" pills or ointments available over the Internet are worthless and should be avoided.