Your ketubah will be shipped flat between foam core, which you can use to safely transport the piece to the wedding, and it's pretty packaging that can be used to display the ketubah at the ceremony. The piece is not matted, but rather secured with photo corners to one of the pieces of foam core.
Some people do prefer to frame before the wedding because the ketubah will be more secure behind glass. If you choose to do that, just let the framer know that you need for the backing to be easy to remove so that you can sign and quickly reconfigure the frame.
I will include an archival ink pen when I send your ketubah, so that you can be sure your signatures will last as long as the artwork.
Be sure your framer uses acid-free, non-buffered, archival quality matte, and ask for UV protected glass. Do not have your ketubah dry mounted. Hang your ketubah away from direct sunlight.