Who Should Sign The Ketubah?
The short answer to the question of, "who should sign the ketubah?" is:
1. Traditionally, the witnesses are the only people who sign it.
2. More recently, rabbis have begun signing it as well.
3. Even more recently, the couples are now more commonly signing it themselves, too.
The Ketubah was traditionally a social document -- a commitment made in front of the entire community. The community is the witness. That's why, the most important part of the Ketubah is the witnesses.
This is a bit similar to the legal notion of a public notary: a commitment is firm and legal when it is witnessed by other people! It's also related to the the Jewish variation of the concept of an oath: making a promise before the others of what you will do.
However, many rabbis -- and, these days, even the couples themselves! -- often love signing it as well.
Here at Ketubah HQ, our general attitude is: the most important part is the witness, and we will never change or sacrifice that.
However, if you want to add in more witnesses; or rabbis or officiants; or the couple themselves -- we'll do it! You need to just let us know! (We'll ask you--so don't worry. We won't forget to make this clear to you!).
Here is an excellent and useful page from Chabad about the text and signing of the Ketubah, including the V'kenina and many other details. You can read it if you want more information but really, you don't need to worry about it since we'll hold your hand and step you through the entire process.