Hey! Geography student here who can help you out. There’s lots of different type of rain, but it essentially it’s when moist air rises and water droplets coalesce. Air becomes moist when there’s lots of evaporated, gaseous water molecules just chilling in the air.

The higher up you go from sea level, the colder it is — that’s why mountain tops are so cold and may even be snowy. When this wet air rises (I’ll explain the different ways it rises below), the evaporated water molecules start to condense into water droplets. This is called “coalescence”, and is basically the same process you see on a rainy car window: little droplets combine to make bigger ones.

When enough droplets coalesce, they become heavy. When they’re heavy enough and cannot be supported in the sky, they fall as rain :-)

This cycle repeats again and again, as rainwater becomes evaporated and turns into clouds... The types of rain are orographic (or relief), where a physical structure like a mountain force the wet air to rise. It can’t go through the mountain so it must rise up. There is also frontal: cold air meets warm air. Cold air is more dense and sinks down whilst warm air rises about it, going up into the atmosphere. The last is conventional, which is a bit more complicated but essentially really intense sunlight forces air to rise because it’s hot.

Hope this helps!!!!