Joplin Server had a feature to share a note by link for a few versions now but it was mostly a beta feature. In Joplin Server 2.0, the feature will be officially released and should be stable.
To share a note, you will need the corresponding desktop application v2.0. Then you can right-click on any note and select "Share note..." from the context menu. You can also select multiple notes, and each will have its own share link.
After that a dialog opens showing you the note - from there you just need to click on "Copy shareable link" to create the share link and copy it to the clipboard.
Note that at the moment sharing a link does not work with End-To-End Encryption. If you share a note, it will always be decrypted, even on the server. This should be addressed in a future version. The URL however is secure - only people you share the URL with will be able to see the note. In other words, it's not possible to guess or discover the URL any other way.
