The command is - 'A'.



or, you can choose from toolbar-

Now, There are two methods of drawing an arc:-
1. 3 Point.
2. Center.

1.3 Point Method:-
                              In this method just select three points after entering the command for arc.





2. Center Method:-
                                 To use center method first choose center mode as shown in the picture below in red box -

                    
*choose the center of arc-

*Select starting point as following-

* Then select end point of the curve.-

and the curve is drawn.