A cemetery is a place where dead people are buried. What was originally meant was the area around a church that was enclosed, for example surrounded by a fence. This is where one of the many other expressions for a cemetery comes from: churchyard. Especially for cemeteries from the Stone Age or ancient times, one also says burial ground.
For most people it is important that the dead are buried in a dignified place. This place should be quiet and peaceful. It is not only about the peace of the dead, but also about the relatives being able to commemorate the deceased undisturbed at the grave.
A cemetery often has a building where a funeral service can be held. The relatives, i.e. family and friends, gather there during a funeral. The coffin with the deceased is also present. They say goodbye together with speeches and songs. Then the coffin is taken to the grave.