Uterine prolapse is a common medical condition. Especially in women who have had spontaneous vaginal deliveries of their children, the "obstetrical trauma" that results can cause numerous changes in the pelvic floor anatomy. I would recommend that you discuss this with your OB/GYN. There are multiple options available, and the right one for you will likely depend on your condition's type and severity.
There are multiple options for uterine prolapse. First, the strengthening of the pelvic floor muscles is key in order to hold the pelvic organs (bladder, uterus and rectum) in their normal place. Strengthening can be done in a formal fashion with Kegel exercises. A trained physical therapist
can help you with these somewhat difficult exercise to learn.
Another option is pessary use. This is the insertion of a small plastic device into the vaginal canal to hold the uterus in place. This can be done with the help of your OB/GYN.
Another option is hysterectomy, or the surgical removal of the uterus. This is the definitive treatment, but obviously has other results (i.e. allows for no further child birth).
Your options depend on the severity of your case, and whether other pelvic floor problems exist. Please talk to your OB. Good luck!