If you are discharged from the military you will need a copy of your DD-214 to prove you left the military in good standing. If you have misplaced your original DD-214 form you can request another copy by completing and submitting Form SF-180 "Request Pertaining to Military Records." You can download Form SF-180 by going to the government's archive website.
You can request it through the mail as well. The street address is:
The National Personnel Records Center
9700 Page Avenue
St. Louis, MO 63132
Great. Or if you already have a VA loan and are just looking to take advantage of a lower interest rate with a streamlined refinance, then you do not need to provide a copy of your DD-214.