If you want to preview your changes before going live, or need to submit a draft for approval, then all pages can be saved as drafts without making the changes appear on the live published website.
After you have made your amends, click Save Draft. You can then use the view options at the bottom right to switch to Preview mode.
While in preview mode, you can toggle between Draft and Published to compare your changes to the current live version. When you have finished, use the view options to change back to Edit mode.
You can also use Split mode (under View options) to have the preview shown alongside the editor, this is only recommended if you have a large screen.
Once you are happy with your changes, click Save & Publish to make them live, or choose Cancel draft changes from the More options link to discard amends since the last published version.
You can easily spot pages that have changes saved in draft as they are marked with a MODIFIED label in the page list.
Note that while you are logged in to the admin area, viewing the website will show the latest draft. If you wish to view the website as the public will see it, be sure to log out first.