Hello

If you mean the birth and marriage certificates of the civil records office, you should look at the Standesamt Würzburg or the Stadtarchiv Würzburg.

By the way there is a database project of the University of Würzburg about Jews in Lower Franconia:
https://www.historisches-unterfranken.uni-wuerzburg.de/juf/Datenbank/
https://www.historisches-unterfranken.uni-wuerzburg.de/juf/Datenbank/juf.php?global=reset

Regards

Corinne Iten
Switzerland