Generally, one might say it was a Nature religion. However, all of life was a spiritual activity, and propitation of spirits and totemic gods was interwoven into many activities.
Apaches generally believe that something larger than themselves created the universe. Creation stories differ from tribe to tribe, but often it seems that the creator formed the universe out of boredom. The spirit realm was a mirror reflection of life on earth. Some Apaches believed in reincarnation but most believed spirits included ancestors, animals, the four directions and natural forces. Virtues in Apache tribes included hard work, keeping your word and generosity. The reward for good acts was not a reward in the afterlife but a reward of good things in present-day life.
The spiritual life of an Apache helped him find his place in the world. Childhood was a time of learning practical skills and the rules of the tribe. But by the time of puberty, Apaches were expected to mature and discover their spiritual paths in life.
This often included fasting and vision quests for the boys. They would get a vision whereby a helpful spirit would reveal itself to be the boy's ally if the boy follows its advice.
Girls didn't have to do this, because they were thought to be spiritually powerful. The elderly of the tribe were to be treated with utmost respect because if they lived that long, then they must have pleased their spirit allies, their totem gods, spirit animals and ancestors.