Commonly vaginal odor is caused due to bacterial vaginosis, yeast infection or sexually transmitted diseases or may be poor hygiene.
See doctor if there is an abnormal or persistent vaginal odor especially if you have other symptoms such as itching, burning or discharge.
Meantime, Keep your external genital area clean. During regular baths or showers, use a very small amount of mild, unscented, antibacterial soap and lots of water.