I don't know why have you removed the watermark option from produce video settings in Camtasia 2.0
Hello,
Watermarks can now be added via the callout tools. However, we are currently looking into re-adding the watermark function from the previous versions.
Thank you for using Camtasia Studio!
-TechSmith Support
How can I make a callout with a transparent color?
When you are adding a callout in the Editor, you can set it's Opacity using the Opacity slider in the Callout Properties.