From May 2017, you can develop app without MAC.
Microsoft Xamarin introduce a Live Player. With Live Player, iOS apps can be deployed directly onto an iPhone or other iDevice from a PC running Visual Studio, where the code can then be tested and debugged.
WARNING The Xamarin Live Player Preview has ended. See discussion
See this video: https://www.youtube.com/watch?v=awgZDL1a3YI
this is Live Player Get start section: Live Player
Note: The final build and submission to the App Store will still require a Mac
Device Requirements
The Xamarin Live Player app supports the following devices:
iOS
- iOS 9.0 or later.
- ARM64 processor.
- Check the App Store for a list of supported devices.
Android
- Android 4.2 or later.
- ARM-v7a, ARM-v8a, ARM64-v8a, x86, or x86_64 processor.
Limitations
There are some limitations on the things Xamarin Live Player can run, including the items below:
- Android user interfaces designed with AXML files are not currently supported.
- Some iOS storyboard features are not supported.
- iOS XIB files are not supported.
- Custom Renderers are not supported.
- Xamarin.Forms Effects are not supported.
- Embedded resources are not supported (ie. embedding images or other resources in a PCL).
- Limited support for reflection (currently affects some popular NuGets, like SQLite and Json.NET). Other NuGets are still supported.
- Some system classes cannot be overridden (for example, you cannot implement a subclass).
- Some platform features that require provisioning can't work in the Xamarin Live Player app (however it has been configured for common operations like camera access).
- Custom targets and build steps are ignored. For example, tools like Fody cannot be incorporated.