There are no real rituals with regards to a Bar/Bat Mitzvah within Jewish Law. Judaism teaches that when a boy reaches the age of thirteen years and one day and when a girl reaches the age of twelve years and one day they automatically become Bar/Bat Mitzvah. That happens regardless of whether they have a party or receive any kind of honor during the Synagogue services. I do imagine that there are probably different customs within the communities as to how to commemorate a Bar/Bat Mitzvah.
It is certainly not obligatory because, as I wrote, turning Bar/ Bat Mitzvah happens automatically regardless of whether anything formal is done or not. However, there is no doubt that it has become the accepted norm and that most children look forward to it and appreciate it very much.
