The Iris Installer

Automatically downloads and installs Iris and Sodium. Run the installer, choose your Minecraft version, and hit install.

Download for Windows.exe installerDownload Universal JARWorks on any platform

Or grab it from a mod platform

Modrinth
ModrinthRecommended mod platform. You will also need Sodium.
CurseForge
CurseForgeAvailable on CurseForge. You will also need Sodium.