Cobalt provides a default e-mail template but you can edit this or create your own to send to contacts who go through the Forgot Password steps on the portal.
View or change the default template on the Setting Entity
Scroll Down to the Portal Configuration Tab and check the link next to Forgot Password Notification
Note the name of the e-mail template but do not access from here. If you want to change the e-mail template you will use the look up button on the right to search for and select the one you want to use instead.
Edit the E-mail Template
Open the Template you wish to edit and add your text.
Make sure you create a link to the Password URL on the contact record. If you are using the default this should be done for you.
The email piece at the start of the merge fields links to the contact record where the URL is generated and stored. When the person clicks Continue on the password reset page of the portal this URL is generated.