I have a problem of irregular mensturation please tell me what to do?

Need to find out why: If not trying to conceive you can take birth control pills to get monthly bleeding. We need to find out why you have irregular cycles: polycystic ovarian sydrome (pcos), underactive thyroid, excess prolactin hormone, aging of the ovary (diminished ovarian reserve), or low hormone levels (hypogonadism) from exercise, eating disorders, stress. See a reproductive endocrinologist for tests / treatment.