PowerPoint has many different options and a lot of these options are changed or moved in new versions. PowerPoint has one option with dual monitors that, upon entering "Presentation Mode", has you split the presentation into two ways. Kinda like this.
PowerPoint 2013 has an option for dual monitor setup and its easy to switch off the presenter view when you don't want it, especially for Zoom screen sharing.
In PowerPoint 2013 or 2010, navigate to the Slide Show Tab and to the far right you should see something like this:
In PowerPoint, we want to just change a few options to make it more suitable for Sharing in Zoom or getting back that "Old School" kind of feel from back in PowerPoint 2003.
By clicking on the drop down menu next to Monitor (For 2013) or Show On: (For 2010) and changing this to Primary Monitor. To Turn off Presenter View, just click the uncheck the box next to where it says "Use Presenter View". Should look like below.
That should do it!
However if you still have trouble getting everyone on one screen, you should also take a look at this Solution article here which shows you how to duplicate/clone monitors instead of extend: https://parkuniversity.freshdesk.com/solution/articles/6000186909-dual-monitors-101-how-to-change-monitor-setups
Written by Shilo Acebedo-Moore