What you are referencing is a
Text Mesh I'm not sure what engine you are using but Unity has a package called TextMesh Pro. It allows you to place text into a 3D space.
What you can do, is provide boundaries for this text and the text will only fill within the boundaries you placed. So, for Russia, you would create the boundaries to outline all of Russia the best you could. Then, you can adjust the font size manually, or set it to best-fit and the engine will create it as large as the boundaries will allow it.
You can also do cool stuff to the text, like outlining the text, giving it a shadow, etc.