Send it to the court, with a copy to the opposing party ... even if you and ex spouse did it together you must formally "serve" a copy on him or his attorney by first class mail, and in your cover letter ask the court to approve it.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.
Both you and your ex should sign the QDRO and have it entered by the judge. After it has been entered with the court, serve a copy of the QDRO on the Plan Administrator. The Plan Administrator will notify the parties (and counsel, if any) if the the QDRO is qualified.
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