It doesn’t matter anymore if you use Windows or Mac OS or which font you use to display a text. It took some time, but today Unicode is the default encoding for basically all electronic communications. Finally in the early 1990s a new system was invented that should overcome all the limitations and incompatibilities of the older codepages: Unicode-a system where all character of all writing systems are combined into one standard. In the 1980s a variety of (largely incompatible) 256 character codepages where used. It all started with 128 ASCII characters in the 1960s.
This articles explains why that happens and what you can do about it.
Your favourite fonts might have glyphs that you don’t know are there, because your character viewer might simply not show them to you.