If you want to limit who can open and view your Keynote presentation, you can protect it with a password. Anyone who receives the presentation from you needs to know the password in order to open it. If you’re sharing your presentation in iCloud, your collaborators also need the password.
Tap 
, then tap Set Password.
Type a password, retype the password, then enter a hint.
Tap Done to return to your presentation.
When you open a password-protected presentation by entering the password, you can turn on “Remember this password” so that you don’t have to type the password each time you open the presentation.
Note: You can add a password after you share a presentation. If you do, be sure to notify collaborators so that they can open the presentation.
Change a password: Tap , then tap Change Password. Enter the required information, then tap Done.
Remove a password: Tap , then turn off Require Password. Type the old password, then tap Done.
Note: A presentation can have only one password, so if you change the password when you share the presentation, that becomes the presentation’s only password.
Password-protected presentations stay protected when you share them using iCloud, so your collaborators will need the password to open the presentation. If the presentation is already being shared in iCloud, you can add, remove, or change a password in Share Settings.