Lucky you -- you are here because you need a QDRO. Usually, when when you need a QDRO it is because you have been awarded a portion of the retirement plan in which your spouse/former spouse is a Participant. Occasionally the participant initiates the QDRO, but nine times out of ten, it's the alternate payee needing assistance to claim their share of the funds.
A QDRO is a Qualified Domestic Relations Order. QDRO is pronounced Quad-row -- it's such a common term these days, I wouldn't be surprised if you find it in Webster's.
QDROs are usually used to divide retirement plans, both defined benefit plans (pensions) and defined contribution plans (often 401k plans). Usually a QDRO is not necessary to divide an IRA account but some investment firms do require them none the less. So best to check with them. Also, some retirement plans, usually pension plans as opposed to 401k type plans require a joinder, legal documents that alert them to the fact the plan may be divided in a divorce or legal separation action.
A QDRO will satisfy the IRS so that a portion of a qualified retirement plan may be transferred from the retirement plan of the participant to the retirement plan of another person (known as the "alternate payee") without triggering any nasty tax consequences.
QDROs may also be used to collect child or spousal support arrearages -- in other words, using a QDRO is a way to collect past due child or spousal support from someone who is hasn't paid in accordance with their court order and is in arrears. In addition to collecting the back support, the law also allows you to be awarded collections fees. This is a little known but very effective way to collect past due support.