Answer #1:
AutoMod is a feature in Discord that allows users to automatically add certain users to channels and servers. It works by monitoring a user’s activity in the server and channel they are added to, and will automatically add them when they are active. This is a great way to make sure that all members of the server are aware of important announcements, and can easily communicate with each other.
Answer #2:
Automod is feature of discord bots where you get a limit of something and if someone exceeds it, bot will warns, mute or ban them as you set it to do.
Understand it with this example.
You have set some words as blacklisted words and set the bot that whomsoever uses it, they will get mute, so here in your server i used that word and bot muted me automatically that automod, here to don’t have use commands manually bot will do on its own.
You can set it with bots dashboard.