Hi andressa,
yes, NGSolve supports hexahedral meshes and the corresponding finite elements are also available.
E.g., with
from ngsolve import *
from ngsolve.meshes import MakeStructured3DMesh
mesh = MakeStructured3DMesh(hexes=True, nx=10,ny=10,nz=10, mapping=lambda x,y,z : (2*x,y,z))
Draw(mesh)
you can generate a box with x-length 2 and y,z-length 1.
Best,
Michael
