The partial atomic charge can be obtained from DFT calculation. You should first set your geometry and then use the CASTEP module (if your geometry is periodic) or the Dmol3 module (if your geometry is a molecule). Based on the selected module, use the Geometry optimization or Energy Task. At the end of the output of these two modules, the partial atomic charge of each atom has been calculated and you can use it! Please don't hesitate if you need help. Good look!