Guide
You can share any Document using a unique URL. Sharing is public and the link never expires (but it can be turned off → see below).
Enabling & disabling sharing with public link
Find the relevant button in the top right corner, enable the link, and share it with anyone outside your workspace:
To disable, click Stop sharing
Sharing via link is sharer-dependent: if the user enabling the public link doesn't have access to a mentioned Entity, it won't be shared.
FAQ
Can external users add comments in a shared Document?
Not at the moment. If you need this, let us know.
How do I know what other people have shared?
Navigate to Settings → Public Sharing.
Check out Public Sharing.
Is shared information indexed?
We put "X-Robots-Tag": "noindex" header for shared documents and entities, which should prevent content from being indexed.
However, we don't recommend publishing sensitive info on the internet on a page that doesn't require authentication.