External LaTeX compilers are often bundled with various other related tools in the form of a TeX distribution.
Various such distributions are available for your Mac, but the one we recommend for its ease of installation is TexLive/MacTeX, www.tug.org/mactex, a packaging of TexLive for macOS.
Texifier macOS is designed to handle multiple installations. These may be selected for the active typesetting via the Preferences’ Distribution pane.