Setting your Units of Measure in AutoCAD is relatively straightforward.
To check the current .dwg file’s units, simply type UNITS into your command line, then choose the units of measure that you wish to use.
When creating a new drawing in AutoCAD, it is important to start with the correct template.
For a Metric (millimetre) template file, select acadiso.dwt
For an Imperial (inch) template file, select acad.dwt