Let others watch
Share a watch-only link. Spectators can vote on the Chaos Director's cards.
Copy the watch link
Any player can open the pause menu and press "Copy spectate link". While you spectate, the "Spectating (click to copy link)" badge at the top of the screen copies the same link.
The watch link is not the invite link. It never lets anyone join the match, and it doesn't reveal the invite link.
Opening it
Opening the link joins the match as a viewer straight away, with no button to press. If the match isn't running anymore, the page says "That spectate link isn't live." A viewer has no invite card of their own.
What spectators can do
They watch the match live. When ghost votes are on, they also vote on the next card, just like players who died. Bots and living players don't.
See the Chaos Director guide for how the votes work, including linking a stream chat.