You're very close, the correct syntax is this:
!Shape!.area
If you're in a Projected Coordinate System, you can also use the "Calculate Geometry" option to get area as well.
Thank you very much Matt. It works fine[ATTACH=CONFIG]34184[/ATTACH]BestJamal
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Jamal Numan
Geomolg Geoportal for Spatial Information
Ramallah, West Bank, Palestine