To share a notebook, you can use the Share menu. Anyone with edit access will be able to edit the notebook, and anyone with view access will only see a view-only version of the notebook.
If you want to update a notebook that you have forked from, click Merge instead of Publish. Publish will publish a new version of your notebook instead of updating the original. Read more about publishing and merging in Version control.
When you publish a notebook the default appearance of the notebook will change:
All visible cell inputs (SQL and drag/drop) will become invisible.
Any linked text will be displayed as the computed value rather than the cell reference.
The side bars will disappear.
If the person viewing your published notebook does not have permission to edit notebooks in the project, they will not see the 'View code' toggle