How can i create a plugin ?
I don't understand your question.
i am trying to make a plugin and i did follow the instruction for this doc :https://moodledev.io/general/app/development/plugins-development-guide
but it does not exist and not shown.
I still don't understand your question. If you are creating a new plugin and an essential file does not exist you would need to create it. For a mobile plugin to work you need it first to work in the browser and then consider mobile. The Moodle Acadamy has a free course on developing plugins, you might want to follow that first and then move on to adapting a working plugin to work with mobile.
Whenever you ask a question here supply as much information as possible, Good luck with your development.
Whenever you ask a question here supply as much information as possible, Good luck with your development.