To do Alt + H + I + D on Mac in PowerPoint, download and install Accelerator Keys, then press Option, followed by H, I, then D.
Command: Duplicate Selected Slides
This is how to do Alt + H + I + D on Mac in PowerPoint with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with PowerPoint.
Alt + H + I + D duplicates the currently selected slide(s) in your presentation. The duplicated slides are inserted immediately after the selected slides, maintaining all content, formatting, and animations. This is useful for creating variations of existing slides or building out similar content quickly.