As this question seems to come up a lot, I've decided to re-post this blog entry from 2015. Please read on to learn about these two important documents!
A civil marriage license and a ketubah serve different purposes but yes, you need both. The civil marriage license registers your marriage as legally valid and binding in the eyes of state and federal law. Participation in your spouse’s health care plan, distribution of benefits, filing of taxes, survivorship, and other matters are all contingent on you having this document. Your ketubah, on the other hand, certifies that you are married in the eyes of the Jewish community. Some rabbis will require a review of your ketubah before allowing you to join their synagogue. Others will require it before admitting your children to religious school. So, you need both!
Where do you get a civil marriage license? The village, town, or county where your ceremony will take place issues your civil marriage license. For example, if you live in Manhattan, but plan on getting married in New Jersey, the issuing authority is the county in New Jersey where you’ll be married. Apply for your marriage license early. Don’t leave it for the week of your wedding as there’s a good chance you might have to wait in line at a government agency, wasting valuable time during an otherwise stressful week. These documents are normally good for 3-4 months, depending on the issuing authority.
Who can sign your marriage license? There will be a place for you and your spouse to sign, and a section to be completed by your officiant. Typically, there will be a place for two witnesses to attest to your marriage. Unlike your ketubah, any adult can sign your wedding license. Give some thought in advance with respect to whom you’d like to sign on your behalf. (Also, see my posts entitled, “Who Gets an Honor at My Wedding?” and “Who Can Sign Your Ketubah?”)
The marriage license, together with your ketubah, will be fully executed immediately prior to your wedding ceremony at your “ketubah signing.” Your officiant will mail the document to the authorities, or may give it to one of your parents to do so.
Finally, don’t assume that you’re married! Well, yes, you’re married at this point, but it can’t hurt to have a written record. A week or two after your wedding, request a certified copy of your marriage license (giving the local authorities time to process it). Your request can take a few weeks, but you should have a copy of your license on file at home.