Where does apersons DNA come from?

A person's DNA comes from their mother and father. 23 chromosomes* come from both mom and dad. Mom provides the egg and dad the sperm as cells that contain the chromosomes. As the sperm enters the egg and dissolves, it releases it's payload of chromosomes causing the egg to have 46 total chromosomes: the perfect number for the egg cell to spring to life and form a human being.

*Simply put, a chromosome is nicely packaged DNA.