Set up measurement scale in Photoshop 20.x

Previously, I have been able to set up a measurement scale in photoshop where one enters the actual width of an object (in this case, inches) to set a measurement scale for the entire image. Then you use the measure tool to determine the true width of other objects in the image. I have looked for menu items to set this up and cannot find thte proper place tp make the settings. Can anyone help?

Thanks to those who know more than me,

Joe Dempsey