The ketubah (plural: ketubot) is a Jewish marriage document that details the mutual responsibilities and commitments spouses make to one another and serves as an extension of their wedding vows. Often an ornately-decorated work of art, the ketubah originally was a legally binding contract; contemporary ketubot often follow the structure of such a contract, which must be witnessed and signed to be valid. Customarily, all or part of the ketubah is read aloud during the wedding ceremony.
The wedding partners honor friends (customarily required to be Jewish and unrelated to the couple) by asking them to sign the document as witnesses. Usually, the witnesses are expected to sign their names in Hebrew, but if you aren’t sure how to do that, ask the wedding couple for guidance and they can speak with their clergy about how to make that work.
The officiating rabbi or cantor will let the couple know what time you should arrive for this honor (usually 30 minutes before the wedding ceremony is scheduled to begin) and will oversee the ketubah-signing ceremony from start to finish. Your job is be present and follow the officiating rabbi or cantor’s instructions, adding your signature where and when they tell you. It is a true honor to be a ketubah signer, reflecting the couple’s deep appreciation of your friendship and connection.