{unicode} is for questions about Unicode (an international standard for character encoding) and its implementations. For questions about input encodings use {input-encodings}.
unicode is for questions about Unicode (an international standard for character encoding) and its implementations. XeTeX and LuaTeX provide Unicode support, thus ConTeXt as well if using one of these engines. For LaTeX, the UTF-8 implementation is the most common, provided by the inputenc package:
\usepackage[utf8]{inputenc}
For questions about input encodings use input-encodings.
