dictionary.com defines "landform" as:
a specific geomorphic feature on the surface of the
earth, ranging from large-scale features such as plains, plateaus, and
mountains to minor features such as hills, valleys, and alluvial fans.
The Wikipedia aericle says:
A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography.
The National Geographic Society says:
A landform is a feature on the Earth's surface that is part of the terrain. Mountains, hills, plateaus, and plains are the four major types of landforms.
Several other dictionaries and reference works define the term "landform" similarly, as a noun. None that I found use or define it as a verb, meaning something like "to form the land".
One can speak of "building mountains" or "forming the terrain" or "shaping the landscape" or any of several other possible expressions.