What purpose does the tail in a sperm serve?

A sperm cell looks like

Since the sperm needs to travel inside the female reproductive system and enter the egg, it has a tail. Tail helps the sperm to move forward (like a snake) instead of moving in circles.

There are other parts of the sperm, like head, neck, middle part  and tail.

The purpose of them is

• Head carries the genetic information,
• Neck contains enzymes
• Middle part supplies energy to the sperm
• Tail helps the sperm to swim in the female genital tract.