Traditionally, a mantra is written in Ranjana script or Tibetan script, on the outside of the wheel. The mantra Om mani padme hum is most commonly used, but other mantras can also be used.

Prayer wheels sometimes depict dakinis and the eight auspicious symbols (ashtamangala). At the core of the cylinder, as the axle of the wheel, is a "life tree" made of wood or metal with mantras written on or wrapped around it.

According to the Tibetan Buddhist tradition, spinning such a wheel will have much the same meritorious effect as orally reciting the prayers.