You can send email invitations/notifications in three places:

• Go to 360° Feedback > Feedbacks and click on the three-dots icon at the end of the row of a given review. A menu will open featuring the following options: Send invitations to all and Send reminder to not completed.
• If you are in the details view of a given review, click on the three-dots menu. A menu will open. Select the appropriate option.
• In the Reporting tab in the details view of a given Reviewee click on the three-dots menu next to the row of a given reviewer. You can send a reminder only to that specific reviewer.

You can set email notification wording in Settings > General > Notifications.

Read this article to learn more about specifying notification wording.