YouTube provides an "auto-caption" feature that works really well, but it does not include capital letters and punctuation. Standards for captioning require 99% accuracy. Thankfully, auto-captions can be edited for accuracy so you don't have to tediously type in your entire transcript. You can just correct the text that's auto-generated.
See the following video (1:16) for more information:
You will also need to create a transcript of your video that is linked either above or below the video. After using the Video Manager to correct your auto-captions in YouTube:
Alternatively, you can follow these directions:
Either of these methods creates a transcript file, but the second method may require some formatting before you can post it.