By ID, I presume you mean InDesign. Go to Preferences (Ctrl/Cmd+K), scroll down to units and increments, change ruler units from picas to inches.
BTW, this is the Creative Cloud forum, for programs specific questions, go to that program's forum. https://forums.adobe.com/welcome
What Robert says would apply to the currently open file.
To do that for all future files you create, do what he says with no files open.
Thank you, Steve. You're correct, of course.