For questions about specific manifestations of magic that we generically call "spells." Use the [magic] tag for more generic questions about magic, and [spellcasting] for questions specifically about the process of spellcasting.
This is a catch-all tag for asking questions about specific spells and the interpretation, uses or effects thereof, or interactions between them.
Questions about the general nature of magic should use magic, instead of spells. Questions specifically about the act or process of spellcasting should use spellcasting instead.
Note that outside some historical, exceptional cases, such as wish or simulacrum, individual spell names should not be used as tags, instead this generic spells tag should be used.