Mobile Application Development Web-base and native

I would like to develop a mobile application that can be accessed via web (for people who do not have smartphones but own phones with capabilities of connecting to the web) and a native version of this application that can make use of mobile device (for e.g android)features it runs on (camera, contact, network connectivity etc). My intention is to build a native application that can store information locally in case where there is an intermittent network connection. I also want to synchronize the data with the hosting database on the back end server.

I do not have much knowledge on mobile application development. I'm still on my research. So I would to know the best tools to do this (web-based and native app) ? I have looked at different examples on youtube but I seem to fail to grasp the concept. I'd really appreciate if I can get a whole logic and the architecture of such application (or examples of similar apps).

Thanks in advance.