Today’s mobile apps are rarely created as text-only. Most of them needs at least in-app icons for toolbars. In many cases you can find graphics for mobile platforms as ready to use resources on the Internet, i.
Standard Xamarin.Forms Xamarin.Forms.Editor control offers edit capabilities similar to Entry but for multiline text. Unfortunately unlike Entry it doesn’t support displaying placeholder text out of the box.
As it’s mentioned in MVVMCross documentation Android is quite specific in terms of navigation requirements. The entry point is statically indicated by MainLauncher = true attribute parameter on the activity.