How to add client cluster ID manually in to Xbee S2C

what are ZDO commands? and from where I will get it?

ZDO commands of Zigbee and ZDO commands of Xbee are same or different?

ZDO commands are ZigBee level transmissions, and are not part of the XBee framework.

You will have to do your own research to learn more about them.

ZDO stands for Zigbee Device Object. It is not an XBee thing but part of the Zigbee standard. It is similar to a set of directions for a specific command.