Click Home tabAnnotation panelDimension Style. Find
In the Dimension Style Manager, select the style you want to change. Click Modify.
In the Modify Dimension Style dialog box, Primary Units tab or Alternate Units tab, under Zero Suppression, select Leading.
Sub-units factor: Sets the number of sub-units to a unit. It is used to display the dimension distance in a sub-unit for distances less than one unit. For example, enter 100 if the suffix is m (meters) and the sub-unit suffix is to display in cm (centimeters).
Sub-units suffix: Includes a suffix to the dimension text sub unit. You can enter text or use control codes to display special symbols. For example, enter cm to for .96m to display as 96cm.