I need to send out a part to a shop which needs to be made and it contains a few holes, threaded and non threaded holes. I have used the hole wizard in the 3D model to show the holes. When I create a hole table table in the drawing, it doesn't state which holes need to be threaded. Am I right to assume that by using the hole wizard, the hole will be only be machined without threads. I know how to create threads but I have no idea how to send it out to the shop so they don't get annoyed and over quote me or something similar to that effect. Can I create a drawing and add notes and arrows on which hole needs to have threads?

Also another question: If I want to use M2.5 screw, what's the hole size I need to make? I saw a chart on google but it said the clearance level have to be 2.9 which I quit didn't get. Or is that something I dont need to worry about as long as I state this hole is M2.5?

Need help here guys.. recent grad.