setting unit in AutoCAD ll 

To set units in AutoCAD, follow these steps:
Open the Drawing Units Dialog Box:
Type UN or UNITS in the command line and press Enter.
Alternatively, you can go to the Format menu and select Units.
Choose the Unit Type:
In the Drawing Units dialog box, you can select the type of units you want to use (e.g., Decimal, Architectural, Engineering, Fractional, or Scientific).
Set the Precision:
Adjust the precision for both length and angle measurements according to your needs.
Select the Insertion Scale:
Choose the appropriate insertion scale that matches the units you are going to draw in (e.g., millimeters, centimeters, meters, inches, feet).
Click OK:
Save the changes and start drawing with the new unit settings