Certainly! Now, embedding Webform html is not recommended. It can cause unwelcome display and delivery issues. So, use the In Email Sign Up Form option instead :)
Mimi links to this form wherever you use: [[subscribe_link]] in your promotion. To add an extra clickable link in the promotion body, just copy and paste:
Send a test to check your work. Feel free to edit the Subscribe here text, too. It’s the visable part of your clickable sign up link.