1.First of all to create water you need water. The sea is the main source. The sun hits the sea water (also known as evaporation)and the water turns into Condensation (Condensation is a type of gas)
2. The condensation goes up in the air and reaches the atmosphere the condensation starts to create clouds. Fast Fact/ Did you ever noticed little bubbles in your cold water when its a hot day,well if you did the bubbles are condensation.
3.When the condensation makes the clouds, and when the condensatian makes enough clouds the clouds form together and create a big cloud and when the big cloud is big enough it starts to rain.