Every share has an Access setting with two values. It's the setting worth getting right, because it decides whether your plans are private or public.

Restricted
Only the email addresses you list can open the share. Someone forwarding the link to a person you didn't list won't get them in.
Use this for anything with a named audience: an administrator, a colleague, a substitute, a parent.
Enter addresses in the Emails box, separated by spaces, commas or new lines.
Open
Anyone with the link can view the plans. There's no check on who they are.
Use this when the audience genuinely is "whoever visits" — a class page, plans linked from your school website. Open is also required to embed your planbook in a website; an embedded planbook can't ask visitors who they are, so a restricted share won't render.
Treat an Open link as public. Links get forwarded, and search engines can find them if they're posted on a public page.
Choosing
Ask who you'd be comfortable reading these plans. If the answer is a specific list of people, choose Restricted and list them. If the answer is "anyone", Open is fine.
Restricted is the safer default, and you can always widen a share later.
Narrowing further
Access controls who. Two other settings control what and how long:
- Hide specific plans when sharing — keep individual lessons out of a share
- Set how long a share stays active — expire the link automatically
Your notes are never visible in a share, whatever the access setting.
Changing your mind
Edit the share to change its access, or delete it to revoke the link outright — that takes effect immediately.