Changing Terrain and Terrian level

I want to know how to change the cliff level, like adjust ground that is at level 0 to level 1. I also what to know how to change the terrain from dirt to snow or dirt to shallow water or deep water.

when you open World Edit either just press 'T' or you can use the menus at the top. Layer - Terrain.

That opens a terrain box at the right. It should have all the options you want.

I recommend looking thru the TERRAIN forum for a list of FAQs and whatnot... ; )

I'm talking about changing terrain and terrain level in-game through triggers

You can do terrain deformations by trigger, but those only affect the height field, I think. So although you could make shallow water into deep water thru them, you can't change cliff levels.

Water would only show up if you had pre-placed it. If you want ground to sink and water to appear, place the water, then press ctrl-shift-W (or go to the advanced menu) to turn off water height limits and bring the ground level back up; this makes it so water is not removed when you place cliffs over it, and cliffs are not created to surround the water (as long as no change in cliff height is necessary to place the water) when you extend water boundaries.

You cannot change tiles in-game.

I saw it done in an Everquest map
You would go through a cave door and it would change the terrian and set new creep, trees, items, buildings, etc. for that area.

Here is a link to the map: vQuest

without looking im sure he made the same terrain and changed camera bounds so it appeared you looked on same terrain but with a different tile, while in real, you were looking @ a whole different part of the map