In order to share a document simply hit the Share button in the top-right corner, and you’ll be presented with the following options: Share... and Share editing...
If you choose Share... you’ll see a pop-up window with following information:
Hit the Share button and the application will generate a shareable link for you (as in the picture below), if you hit the Cancel button the sharing operation will be canceled, the link will not be generated and the document won't be shared.
Please take note that the generated document will be Read-Only, and will lead to the document at the state that it was shared. If you make any further changes to your document, these won't be automatically shared until you do another Share… operation. This allows you to continue working on draft changes, and only update the read-only shared version when you want to.
The Copy button places the URL link on the system clipboard. Or if you want to open it in a new browser tab just click the generated share link.
If you accidentally close the window, without copying your share link, you can always go back to the Share menu by hitting the Share button in top-right corner, and selecting the Share... option. The share link is saved with the document, and you can access it every time you want to share the document with another person.
What you can also notice when you enter the share menu for the second time, there will be an Update button within the pop-up window.
If you performed any changes to the document, you can apply those to your shared link by hitting the Update button.
Watch this movie tutorial for an overview of saving and sharing
Check out these articles for more info on document sharing and collaboration...