Yes. It has to be an oil-based colorant and there is no guarantee of the outcome depending on the brand as this is not what they are meant for. If you are making candles as a craft to sell it is much cheaper and more effective to use candle dye.
But for yourself, this is ok and better than crayons! Do not use crayons. They clog the wick. Who wants to smell burnt crayons anyway? Yuck.
If you are making candles professionally to sell, use candle dye.