Google Slides
Google Slides Is A Free Online Colaborative Presentation Tool
And With Google Slides You Can Make Anything You Want
For Example Like You Are A Math Teacher You Can Make A Math Table Game
You Can Do Many Things With Google Slides For Example Lessons , Games..
I Once Made A Game In Google Slides It Was Great As A Simple Game
It's Like A Free Version Of PowerPoint
You can make lessons for free there are many options to choose
and its safe and it is from google.