Helheim was one of the Nine Worlds in Norse mythology. The Norse Helheim was the place that people desired to go the least.
There were probably two ways to understand the meaning of Helheim. First, it meant the Hidden Home. Because in Old Norse, “Hel” meant “Hidden” while “Heim” referred to “Home”. In terms of physical graves, Helheim located underground and that literally meant the hidden home. The other meaning of it was the Home of Hel. And Hel was the queen presiding over the land of Helheim. Hel was the daughter of Loki and gods banished her to the Norse Helheim. There, she gradually built up her own army, waiting for Ragnarok to come. There was a dog Garm guarding the gate of Helheim.
According to the Prose Edda, a source for Norse myth, the Norsemen that died because of sickness or old age would go to Helheim with Hel. Meanwhile, the warriors who died honorably would go with Odin to dwell in Valhalla. But this hasn’t satisfied many because they still question the Death of Baldur. When Baldur son of Odin was unintentionally killed by his brother, Baldur must go to live with Hel in Helheim. This somewhat contradicted to the explanation of who to go to Hel. Life in Hel was just the life in another place with the different dimension. People kept doing the same stuff, for example eating, drinking, sleeping, or fighting. But it was also said that the dead in Helheim could no longer feel joy and happiness.