Islands/Continents how to keep shapes?

hi,

I have kind of a world map with serveral islands and continents.
All the shapes are already existing in one layout and extent - now how can I add mountains, beaches, etc. to
these shapes, without loosing their original outline/shape-borders?

What I got now, are just straight extruded shapes
Is there a way to kind of mask this and let the mountain-noises appear only in some specified regions and then fade out to the borders of the shape?

Imagine our world, just with “blank and even” continents - now you want to apply some mountains, where the rocky-mountains are, add
rivers, where the amazonas is, deserts and dunes, where africa is and so on…

How you do that in WM, without loosing the overall shape of a continent?
How do you add beaches on an island, without loosing the overall shape?

Cheers!

My solution was to have a base island or continent, put a mountain on it, and then add any extra terrain added by the mountain. In practice you let your mountains draw the outline of your islands. Otherwise I’ve found any kind of method to “cut” the mountain so that it fits the base island too rough.

Sorry, I do not understand, what you mean…

I mean that personally I’ve found no decent way to crop a mountain so that the shape of continent is preserved, rather I let the mountain merge with the continent itself. Otherwise I didn’t understand your request.

right, mountains should softly merge with continent