You cannot password-protect PowerPoint for Mac presentations

SUMMARY

Some programs provide the ability to password-protect files that are created in that program. Microsoft PowerPoint does not provide any password protection capabilities for presentations.

PowerPoint also does not provide the ability to protect the contents of a presentation from modification. You cannot have a presentation that you can view but not edit. When you open a PowerPoint presentation, you can always edit the contents.

NOTE: PowerPoint does provide the ability to password-protect macro code that is stored within a presentation.