HI Akshay,
In case you have not already checked, see the steps for customizing Moodle mobile as detailed by Juan in the below link -
https://docs.google.com/presentation/d/1HX5h7zwtay4amaY3qyLuCLfI7kQCiD9IoWuDH-lSa_0/edit#slide=id.p
It is actually pretty straight forward using phone-gap (at least for android). If you are trying to generate apk locally (using android sdk/cordova), there is whole lot of installs & dependencies you need to satisfy to get the apk generated but can be done.