MacTeXをインストール

Homebrewを使う。まずパッケージがあるかサーチしてみると…

$ brew search latex
latex2html latex2rtf latexila latexml rtf2latex2e

If you meant "latex" specifically:
Installing TeX from source is weird and gross, requires a lot of patches,
and only builds 32-bit (and thus can't use Homebrew dependencies)

We recommend using a MacTeX distribution: https://www.tug.org/mactex/

You can install it with Homebrew-Cask:
 brew cask install mactex

MacTexのほうがいいと言われるので、従う。

$ brew cask install mactex

パスワードを聞かれる。