When you draw a shape,maybe,you'll draw some same style shapes.you can set the base style of TMyCAD setting before draw it.you can set Brush,Pen,Font properties of tcad first,then when you draw a new shape,it will be effective.
If you draw a line style,you can set ArrowAngle,ArrowLength,ArrowOffset,ArrowStyle properties besides above properties.
Also,you can do it by code.
procedure TMainFrm.Button1Click(Sender: TObject);
//Draw a line