An anniversary as the term suggests, is the day of the anniversary of the special day a person was born. Although not universal, birthdays are celebrated in plenty of cultures, often with party or in some cases, a rite of passage. Even the great religious traditions, like the Buddhist or Christians celebrate the birth of their founders, the most obvious example is Christmas, principled opposition to the whole idea of celebrating birthdays in positive religious groups. People are invited to celebrate this day.
The birthday cake is historicallyin the past highly decorated, & usually covered with lit candles when introduced, the number of candles symbolize age celebrants. The person whose birthday it is permissible to make this wish & then blow out the candles. So the who presents to open. It is also customary for the person celebrating their birthday on the first part of the cake as a newlywed couple can cut a wedding cake.
Each item was associated with a prediction. For example, finding a person a gold coin with a birthday cake would supposedly become rich, a person discovering a thimble would seldom marry.
Sometimes, in lieu of plenty of individual candles, specialty candles in the shape of a figure used to decorate the cake. For example on the first anniversary can be a candle on the cake in the shape of a figure, & at0 days, clothes, flowers, technical equipment, etc. But sometimes it is to be expected of the person celebrating their birthday at their party guests in lieu, it depends on the local culture to treat the party gifts or other gestures that invite to the bar or restaurant, (a number of them offer special jubilee programs), the controlling party at home or at work .
In most English speaking countries it is traditional for the song to sing birthday song for you to honor person celebrating a birthday.