• Audience members can view a presentation on their devices and read live subtitles in their preferred language while you talk with Live Presentations in PowerPoint. On mobile devices, they can 'pinch to zoom' to see the slides more clearly, provide input, send live reactions to the presenter, and travel back to review earlier slides using 'pinch to zoom.' To begin using Live Presentations, go to the Slide Show option in PowerPoint for the Web and open your slide deck.
• Check your audience settings first. To decide who should be able to connect to this presentation, click the drop arrow next to Present Live.
• Select Present Live next, and your presentation will begin with a screen displaying a personalised QR code. From the slideshow toolbar, you may also start your Live presentation:
• Your audience can use their device cameras to scan the QR code, then press the link that displays over the QR code to open PowerPoint Live on their web browser. They won't be able to install anything.

Read More: How you can record a slide show in PowerPoint?