The email tool allows you to send email to other people in your course without launching a separate email program.

Learn more (students): https://help.blackboard.com/Learn/Student/Interact/Email

Learn more (instructors): https://help.blackboard.com/Learn/Instructor/Interact/Email

Transcript:
You can use the email tool to send email to other members of your course without launching a separate email program. Let’s take a look.
In order to use the Send Email tool, you must first have an email address associated with your Blackboard Learn account. To verify this, open the user menu and select Personal Information under the Settings heading. Next, select Edit Personal Information and verify that your email address in the Email field is correct. Likewise, the Send Email tool will only send email messages to users who have this field completed with their correct email address.
Blackboard Learn keeps no record of your email, whether you send or receive it. When you send email using the Send Email tool, the recipients receive it in their external email accounts, and replies go to your email account, not to the course. Be sure to keep a copy of important messages in case you need them at a later date.
You can access the Send Email tool from the user menu. Select Send Email under the Tools heading, and then select a course or organization.
You can send email to all users in your course, all groups, specific user roles, or to specific users or groups. Instructors can limit the ability of students to send email to various groups of users in the course.
When selecting specific users or groups, choose your recipients.
Next, type the subject of your email, and then compose your message. You can use the functions in the editor to format your text.
Select Attach a file to include attachments with your email.
When you are finished, select Submit. A success message appears at the top of the page. The message isn't a confirmation that any users received the message, just that the message was sent.