Difference in column and shear wall

first it depends up on the building type and next installation of walls it canbe easily decided by the structural engineer very effectively

Sairaj83In Etabs on what basis user can decide wheather to build the vertical element as column or shear wall and in a building what basis the number of columns and shear wall decided.

can't say about etabs but in a building the number of columns and shear walls is decided such that the center of mass (cg) and center of stiffness coincide, so that under lateral loads (earthquake) no torsion is induced in the structure.