The function of a hair follicle is to grow your hair. A hair follicle is a tube-like structure (pore) that surrounds the root and strand of a hair. Humans are born with over 5 million hair follicles in the body and over one million hair follicles on the head. As people age, hair grows out of hair follicles. A hair follicle is one of a few structures in the body that can stop functioning and begin functioning again (degenerate and regenerate). This process helps with hair growth in the body.

Source: My Cleveland Clinic