In an orthographic drawing, you can add dimensions in the orthographic viewports as you can in any AutoCAD drawing. For more information about adding dimensions in drawings, search for About Dimensioning in the AutoCAD Help system. Your CAD administrator has probably set up the default dimension style from the Ortho Settings dialog in the DWT.
Make sure you are in paper space when adding dimensions.
Dimensions do not update when the model updates. You must adjust the dimensions manually.