Hi , I am keen to understand on how I can import or export process m

Mukesh, as you told, all the components on Appian are exported using a Zip file. Those components is a lot of XML files using BPM 2.0 convention and all the tags insidethe files follow that convention.
Appian have a particular way to group this information and create a Zip file.
If the other tool support import using Xml files in BPM 2.0 convention, you can import Appian models in other tool and vice versa is real too.
You can get the Xml file exported to the other tool and import on Appian if this file follow that convention.
I hope this information help you.
Regards

I read some where that Appian process models/applicatioons can also me exported/imported in XPDL format. Most of the other BPM tools support this standard. Can you let us know if we can import the application/process in XPDL abd How?

I cannot confirm if XPDL is the structure, I'm sorry. I just know if the XML file is in the BPM 2.0 compliance, you can import on Appian with no problems.

Appian has it's own XML format that uses concepts from BPMN 2.0 but does not follow exactly. BPMN 2.0 conformance is divided into several categories. Appian is conformant with the Descriptive class, meaning that our graphical notation follows BPMN 2.0. To create an export from another XML format to Appian, you will need to create an XML transformation (XSLT) to migrate the objects. Appian performed this once with Mega, allowing processes from Mega to be imported to Appian and vice versa using this technique. Appian has not provided a XPDL or other format importer/exporter due to a general lack of demand.

Thanks Malcolm, this information is useful. Also i am looking for a way to export/import XML file in ZIP created by Appian corresponds to the BPEL (ver?) specification? Wanted to understand if there a way to export and import Appian process or complete application to other BPEL/BPMN 2.0 compliant tools or vice versa.for that do we need to create XML transformation (XSLT) to migrate the objects from and to Appian from other BPMN/BPEL compliant tool?