Hi Dhammika, I directed you to this forum so others would benefit from my/any response.
1. In Moodle mobile 3.5, is it require to set up the development environment?
Yes. I have the whole ionic/server/chrome thing as described here
2. is it need to develop a remote add-on for the plugin to mobile support?
The terminology has changed, but as of 3.5 you can put everything in your plugin. You can see examples of the new way of doing it with
3. I am confusing how to start to Moodle mobile plugin development. So can you please mention steps need to do?.
4. Is there any template for Moodle mobile plugins can use for customization?
See my answer to question 2....
Please post again saying what type of plugin you are hoping to develop and you may get some more specific help.