It's easy to create the holes on the cylinder.
follow these steps.
Answered with a tutorial: https://grabcad.com/tutorials/how-can-a-hole-be-created-on-a-cylinder
Attachmentscylinder_hole.prt.1, 90.2 KB
Your'e welcome nisheeth
Yeah .He's right.Just make sure that you attach these reference green squares to the planes or surface and it will work.
CLICK HOLE,than for first reference select axis of the cylinder,and as a second reference whatever plane you prefer of the cylinder.
but how to make hole on the OD of the Cylinder?