Answer:
This is what i found!
In the Secret Annexe, where the Frank family and others were hiding from the Nazis during World War II, the residents would have had to keep their celebrations discreet to avoid drawing attention to themselves. It is not specified in Anne Frank's diary how they celebrated Otto Frank's birthday, but it is likely that they would have kept any celebrations low-key and made little noise. They may have shared a small cake or special meal together, but they would have had to be careful not to make too much noise or attract the attention of anyone outside the Annexe.