The Mark as Final command makes a presentation read-only — so that others can read it, but not change it — but it is not a security feature. To determine whether a presentation is marked as final, look for the Marked as Final notification at the top of the PowerPoint window, just below the ribbon commands.
You or anyone who receives an electronic copy of a presentation can reverse the Marked as Final status and edit the presentation. To do so, simply click Edit Anyway.
Here’s how to mark a presentation as final:
Open the presentation, click the File tab, and then click Info.
Click Protect Presentation, and then click Mark as Final.
To unlock a presentation that’s marked as final and make it writable again, repeat the steps to mark a presentation as final. For more details, see Edit a presentation that is set as ‘read-only’.