why you want to access the font file?
If you want to use your font you can use embedded fonts.
just add the "icons1.ttf" to the shared projects's folder and set it to EmbeddedResource.
and add the code to anywhere in your code file.
[assembly: ExportFont("icons1.ttf", Alias = "icons1")]
Then you can use it in your Label.
please check the url:https://devblogs.microsoft.com/xamarin/embedded-fonts-xamarin-forms/