Password-protect a Numbers spreadsheet on iPhone
You can assign a password to a spreadsheet so only those who know the password can open the spreadsheet. Passwords can consist of almost any combination of numbers, uppercase or lowercase letters, and special keyboard characters.
A spreadsheet can have only one password. If you change an existing password when you share a spreadsheet with others, the new password replaces the original. If you add a password after you share a spreadsheet, be sure to notify participants.
Important: There’s no way to recover your password if you forget it. Be sure to choose a password you won’t forget, or write the password down in a safe place.
If your iPhone has Face ID (the face detection feature) or Touch ID (the fingerprint detection feature), you can use it to open password-protected spreadsheets. For information on setting up Face ID or Touch ID, see the user guide for your device.
If you add a password to a spreadsheet, or change an existing password, it applies only to that version of the spreadsheet and to subsequent versions.
If the spreadsheet is shared, to prevent others from restoring an unprotected version of the spreadsheet or a version with an older password, stop sharing the spreadsheet, add a unique password to it, then share the spreadsheet again.