The combined effect of the Moon and the sun's gravitational pull and the earth's rotation causes Ocean's rise and fall which results in Tides. This is also because of the moon's different phases. As moon is very close to earth it causes the highest rise in oceans when it is a full moon. Oceans are pulled upwards making the water bodies bump, which results in high tides in the areas where the Earth is facing the Moon.
The time when the Moon is on the front side or back side of the Earth then they work together, and we get the ""spring tides"" which are specially high and specially low. This repeatsevery fourteen days when both sun and moon are aligned.
