Difference between power bi embedded and power bi embed option in the service

Can anyone tell me actual difference btw power bi embedded and embed option that is available in power bi service.

Which one asks for power bi account when an end user tries to view the content?

which one is of less cost?

This doubt came to me because, we developed a report and used the HTML code to push the report in a secured website.

Power bi embedded also does the same which requires AAD and pro license.