If one or more area and/or line features are selected with the Digitizer tool, the Add/Update the Measure Attributes of Selected Feature(s) option will appear on the menu when right-clicking. Selecting this option will add measurement attributes to the selected features that do not already have them, or update the measurement attributes of features that do. The measure attributes include LENGTH for lines and PERIMETER and ENCLOSED_AREA for areas.
In addition to adding/updating the measure attributes for the selected feature(s), the combined length and/or enclosed area of the selected line and area features will also be reported by this command.
You can also select the Display Feature Measurements option to display a dialog (pictured below) listing the measurements and attributes of each selected line and area feature as well as the total combined enclosed area and perimeter/length of the features. This dialog also allows you to easily export the results to a CSV file.
Choosing the MEASURE - Display Feature
Measurements… option will also populate the Selected Feature Information
window (above), which will display the selected feature measurements and
allow you to export these values to a CSV file.