Ripple Ribbon is the name of Javelyn's Daydream, an ability that comes from her psyche. With it, she's able to remove water from inside her body, being then able to control it.
Her water is still affected by gravity, thus needing to be in contact with either her body or a solid surface to be easily controlled. If it gets too far away from her, it stops being part of her body, becoming unable to be controlled again.