A canyon can be formed where the water eats away on the rocks.
caneons and platueos
Deltas and caves. 😁
canyons and plateaus
mountains and volcanoes
EVERYWHERE
If given enough time, the river will erode the area, but before that it will either run over the area if there is enough water, or will form a lake when it doesn't have enough water to continue.
A rock that erodes to expose layering is called a tilted rock. Tilted rocks are usually formed when tectonic plates push against each other, +++ Sorry but that answer muddles two mechanisms. Layered rocks are normally the sedimentary ones, irrespective of dip (the "tilt"), though volcanic eruptions can also create layers of lava and ash. Yes, plate tectonics do tilt the rocks. Sedimentary rocks are normally deposited in horizontal beds - but uplift and folding from continental collision ("plates pushing against each other") or continental-plate warping tip the affected area of crust and cover rocks, sedimentary or not.
The Mississippi river delta.
lake
Canyon
A gully starts when water erodes the soil and makes it fall into valleys and hills. The amount of water is usually substantial making a permanent change in the landscape of the area.
Rills are formed by erosion. As soil erodes a thin channel is left, this channel fills with water. Gullies are formed by running water. An area where many rills have formed can turn into a gully.