You can use the Rich Content Editor to record audio. The Rich Content Editor is used in features that support the editor (Announcements, Assignments, Discussions, Pages, Quizzes, or Syllabus).
Open Rich Content Editor
Open the Rich Content Editor using one of the Canvas features which support the Editor.
Allow Adobe Flash Player Access
Click Allow to give the Adobe Flash Player access to your computer's camera and microphone.
You can open the Settings for the Flash Player to select specific options for your audio recording.
To open the settings, Right-click (PC users) or Control-click (MAC users) anywhere on the media window.
The time  and the volume level  of your recording will continuously update as you record. Click anywhere to stop recording.
Your recording will begin to playback automatically. Click Save to save your audio recording . Click Record  to re-record your audio message.
Click the Save button to save any changes to the post made in the Rich Content Editor.
Note: When using the Rich Content Editor in Assignments, Discussions, Pages, and Quizzes, you have the option to Save & Publish. When using the Rich Content Editor in the Syllabus and Discussions pages, the Save button may appear as “Update Syllabus” or “Post Reply”.