New guy with questions

Hi I'm new to this group and I have a few questions that may seem so
basic it will probably be ignored. But here goes . . .

How do I tap a hole (in plain cold rolled steel) with a tap? Could I
do this with a wrench?

What is the standard (or at least most popular) program for CNC
machines? Just like how AutoCAD is the standard for CAD drawing.

What is a good price guide that machining services charge?

I have been making CAD drawings and 3D models of a part I might have
to make if it isn't available for buying later.

Thanks!
-GM4T