While the wedding itself is depicted in the movie "Star Wars: Episode III – Revenge of the Sith," the ceremony appears to be just the two of them, officiated by a priestess on the planet Naboo.
However, there is speculation among fans about possible witnesses. Some believe that C-3PO and R2-D2 might have been present, although there's no confirmation from the source material.
Ultimately, the only witnesses confirmed to be present at the wedding are Anakin and Padmé themselves.