Power point is a perfect way to present something visible in a digital way.

The sites listed below are the site when you can download already presentations you have to do now is to reedit it for your own use
1. PPtsearch365.com

2  Xpowerpoint.com

3. Engineeringppt.net

4. Slideshare.com

5. Authorstream.com
 
6. Powershow.com