I’m presuming you mean having a vision of a future event in dreams or in meditations. Having visions of future events in this manner is a form of clairvoyance – the real life psychic ability to see with extra sensory perception. If you are a practicing clairvoyant, you can shift into an envisioning state at will. But if you are not yet aware of having any psychic ability, you will be more likely to experience random premonitions in dreams from time to time.