I an application demo video, I want to add annotations (Text notes, basic shapes etc) on already recorded video. Is there any free software available for that on Windows? I found some, but they work on desktop screen capturing... but I want to work on existing video. I tried with Youtube. I'm able to add annotations but if I download the video from YouTube, they are not there / or downloaded as separate file. I need single video file with my annotation added to the same.
Take a look at Blender or Lightworks (both free). You can import footage and add text or shapes (simple one with Lightworks) to it.