You will notice that there are three buttons in the layout editor above: Save as Draft, Save and Publish and Preview Mode On / Off. Let’s understand their use:
Save As Draft: Your layout is saved by this but it will not get public visible on the website. You can see the draft changes on preview mode. This is useful when you are making changes to the layout and you do not want the general user to see that change before it is final.
Save and Publish: This not only saves the changes but also makes your changes publicly visible as well. When you are confident that the changes you have made are ok, then click on Save and Publish.
If you have made changes to the layout and have not published them yet, then a Publish button will appear in front of each such layout. Something like this:
This helps to distinguish between the difference between the layout saved in the draft and the one appearing on the website. The changes are applied on the website when you click the publish button.