What are Deeplinks?
Deeplinks create a URL that can directly link to a document, page, or even the selected block inside the Craft app itself - clicking on them from anywhere on your system should open the Craft app to that point.
They have the form craftdocs://open… and will work on iOS/iPadOS/macOS. They can be shared between anyone who has access to edit that space. They are typically used to connect other apps back into Craft - for example a Things project can have a link back in the notes section that opens the Craft document that you're keeping notes on that project in. They are not to be confused with Secret Links which open a page on the web for your document for viewing/commenting, not in the craft editor.
Deeplinks are available in the File menu on macOS
If at the time you activate this you’ve got a particular block highlighted (or you’re editing that block) then the Deeplink will point to that. Otherwise, the link will point to the page/document you’re looking at.
On iOS and iPadOS you can get the Deeplink by tapping on the share icon on the top right to open the share menu, selecting “Export as” and scrolling down to "Advanced" and then “Copy Deeplink” button.
Deeplinks can be used pretty much anywhere that highlights links. For example, copying and pasting the Deeplink URL into the URL bar of your browser will open Craft. Placing the link in a Stickys note will allow you quickly access the document from there. You can slack your co-workers or Message your spouse the Deeplink URL and as long as they have access to that space they’ll be able to click on it.
Note: Deeplinks are only available for Craft on Mac, iOS and iPad.
Special thanks for the article to Mark Fowler.