Hi Nima,
Thank you for your update.
We have already provided support for SfRichTextBoxAdv control in Universal Windows platform and is included with our Essential Studio for UWP. You can download it from the following link.
http://www.syncfusion.com/downloads/uwp
You can use our UWP assemblies for building Universal Windows applications.
Please let us know if you have any other questions.
Regards,
Arumuga Perumal S.