You can add a clickable email link in the same way:
Simply type the email address into a text field followed by a space or line break. Teamup recognizes the format as an email address and makes it a clickable email link.
Or, enter any text, select it, click the link button and enter mailto:bob@teamup.com in the URL field (replacing the example email address with the one you wish to use).
This will make your selected text a clickable email link.