Go to filter, scroll to Digimarc, choose embed Watermark.
Below is probably the information you already read, but just in case here it is again:
You can add copyright information to Photoshop images and notify users that an image is copyright-protected via a digital watermark that uses Digimarc ImageBridge technology. The watermark—a digital code added as noise to the image—is virtually imperceptible to the human eye. The Digimarc watermark is durable in both digital and printed forms, surviving typical image edits and file format conversions.
Embedding a digital watermark in an image lets viewers obtain information about the creator of the image. This feature is particularly valuable to image creators who license their work to others. Copying an image with an embedded watermark also copies the watermark and any information associated with it.
For more detailed information on embedding Digimarc digital watermarks, refer to the Digimarc website at www.digimarc.com.