The Preview and Access Control tab of the Pages editor shows you a preview of what the page looks like and allows you to change who has access to the page.
On the left is the preview pane and two boxes:
The first box contains the
URL (address) of the page, which you can copy and send to other people.
The second box contains
HTML you can copy and paste if you want to embed this page into another webpage.
The HTML provided will create an <iframe> (embedded frame) on your page 600 pixels in height and 100% of the available width. You can alter the dimensions by editing the width and height attributes in the HTML or by using CSS on your own page. Embedded pages do not include the page title/header.
On the right you can choose who can access the page:
Anyone makes the page accessible to anyone who knows the
URL. No login will be required.
All users makes the page require a login, but allows any registered user on your account to access it.
Only certain users lets you choose exactly which users should be allowed access. Login will be required.
There is an option to include a sidebar on the page. If enabled, the page will include a menu on the left (or on the top on mobile devices) that includes links to all other pages the current user has access to.