Many causes are possible, the color itself is not significant, however if accompanied with other symptoms, it can guide help identify the cause.
Is there any itching, burning sensation, pain inside or around the vagina, frequent urination, or pain when urinating? Have you used any feminine gels recently or any perfumes or soaps? Are you sexually active? Are you using any medicine?
-cloudy or yellow discharge +bleeding between menses+urinary incontinense. Could be sexually transmitted infections like gonorrhea.
-Frothy, yellow or greenish with a bad smell+Pain and itching while urinating. Might be trichomoniasis.
-White, gray, or yellow with fishy odor+Itching or burning, redness and swelling of the vagina or vulva. Could be bacterial vaginosis.
The best way to tell what the cause is is to check with your doctor to give the necessary treatment due to the specific cause.