OneNote lets you password protect an individual section, which is useful for keeping something like personal notes, HR details, or sensitive planning information behind a lock even inside a notebook that other people can otherwise browse freely. The feature works at the section level only, not for a whole notebook or a single page, and it still works exactly as described in older guides today.
How to set it up
Right click the section tab you want to protect and choose Password Protect This Section. In the panel that opens on the right, select Set Password, enter the password, and confirm it by typing it again. Once set, the section encrypts, and anyone opening that notebook, including you, needs the password to view its contents.
Locking it manually
A protected section stays unlocked for a period of time after you enter the password correctly, rather than re-locking the instant you click away, which is convenient but worth knowing about if you are stepping away from a shared or public computer. To lock it immediately, press Ctrl+Alt+L, or right click the section and choose Password Protect then Lock All.
The one thing to be careful about
There is no recovery path if you forget the password. Not even Microsoft support can unlock a protected section for you, since the encryption is genuinely tied to that password. Store it in a proper password manager rather than relying on memory, especially for a section you do not open often.
It is also worth knowing that some OneNote features, including search and audio recording, are disabled inside a protected section while it is locked, so it is not the right fit for a section you need to search across regularly alongside the rest of the notebook.
If your team is using OneNote for anything genuinely sensitive on a regular basis, it is worth a conversation about whether a properly governed SharePoint or Teams structure is a better long term fit than notebook level passwords. Our coaching and enablement service can help you figure that out. Get in touch if you want to talk it through.