If you in ArcGIS 10 and are using the parcel fabric, you can just use the tool on the parcel editor toolbar. Otherwise, I am not sure. There must be scripts available for that.
You can use the Attribute Assistant's Generate ID function. I use it when I create a new address point. The Attribute Assistant is an add-in that is part of the local government templates. Try here.
Let me explain my problem bit detail as I am not that good in english
I am having aquaculture farm polygons as shape file. Each farm is having a unique 14 digit id (example AA1111111B1111). Each farm is again divided into ponds. I need to give unique id for these ponds; such a way a 3 digit number is appended to the id of the farm in which the pond is located. Example AA1111111B1111001). The order of the numbering is given in the figure attached here with. Thanks to all for your support Regards Sam
Sam, I think you could still use the Attribute Assistant. It works as an add-in and uses a couple of tables that you add to your map. Here is the documentation pdf. The tables are DynamicValue and GenerateID. The pdf explains what fields need to be in each table. There is a post here that states what the field names need to be in the GenerateID table (I had trouble with the field names not working). The pdf explains how the different value methods work. You may need to use a combination of methods to get what you need. I use it to generate new ids for my address points and populating the street name, direction, city, zip fields. It took me a while to get it to work, but once I did it was worth the effort.