As it is, our tides are caused by the moon and the sun together. The sun is farther away so has less influence, the moon has more influence. But when the moon and sun are both on the same side of earth, their gravities add and tides are stronger. When theyy are on opposite sides, their gravities cancel each other out and the tides are less. Every month tides get higher and higher for two weeks, then lower and lower for two weeks as the sun and moon go into and out of phase.
With two moons, you'd have three gravities either adding or subtracting, so the tides would be a lot more complicated. At some times the moons would be togehter in the sky and the tides would be a lot stronger. Other times the moons would oppose each other and cancel each other out. And you'd still have the sun exerting its influence.