Today I downloaded a font to try it in my project. I copied it to Fonts directory, and replaced previous font with this one. But now the text is not displayed. I checked the bundled fonts and noticed they have a png and an sdf files. Do I need to pass the font through some tool to use it in Urho3d?
Well, I can answer myself: I modified the style and the fonts seems to work correctly. Probably it is my mistake.
I used two programs to generate fonts for urho3d.
Their names do not remember.
But I had a old video on youtube where I made new font based on Comic Sans Font 
[video]https://www.youtube.com/watch?v=YOf6fUuNK6U[/video]