zsh-autosuggestions: How to install zpty module? I love zsh-autosuggestions and found in the README:

completion: Chooses a suggestion based on what tab-completion would
suggest. (requires zpty module)

With a web search I din't find out what zpty is and how to install it on macOS. Homebrew prefered.
zpty
zsh: command not found: zpty

If that matters, I am a oh-my-zsh user on latest macOS.
zpty is a module that comes bundled with Zsh since version 3.1. That text you quote just means that if you don't have Zsh 3.1 or later installed, you cannot use that particular feature of zsh-autosuggestions.
If you do have Zsh 3.1 or later installed, then there's nothing else you need to do to use that feature. zsh-autosuggestions takes care itself of loading zpty when it needs it.