A more detailed one: in General data - Analysis information - Solution you can check/uncheck a box named "Geometrically nonlinear analysis". If enabled, the equilibrum on deformed geometry is considered even during each iteration. If disabled, the geometry from the end of the previous load step is used during the iterations.

i would like to ask, the program ATENA 3D take into consideration the geometric nonlinearity in addition to material nonlinearity?

Thanks