There is a offline solution if you are looking for, the app is Calibre. It is basically ebook manager & extra. It can convert the PDF into mobi and customizable

There is a offline solution if you are looking for, the app is Calibre. It is basically ebook manager & extra. It can convert the PDF into mobi and customizable based on your preference. They have a preset for Kindles. Also it can works with DRM'ed files via DeDRM plugins. And Calibre can export it directly to your Kindle. A fair warning, don't use Calibre if you structured your ebook folder. The app will import everything and keep it within their own database folder thus doubling the space size.