You can create an email message in Mail and include your movie as an attachment.
Choose Share > Email.
Choose the video size to export via the Size pop-up menu.
Choose a rendering quality from the Compression pop-up menu: “Faster encode (single pass)” when you are willing to sacrifice quality for faster processing, or “Better quality (multi-pass).”
If you’ve set In and Out points in the Timeline, use the Duration pop-up menu to choose whether to export the entre sequence or the portion between the In and Out points.
To specify additional Motion-specific options, click Render.
For more information about options available in the Render pane, see Render Options for Sharing.
To use background rendering, click Advanced.
For more information about background rendering, see Background Rendering
To see details about files to be output, including the attachment’s estimated file size, click Summary.
Important: Many email services limit the file size for attachments. If the message exceeds the maximum size allowed by your email provider, the message size in Mail appears in red, along with the allowed limit (if Mail can get that information from the email provider).
To see the attachment’s estimated file size, choose your preferred Size and Compression options, then click Summary.
Click Compose Message.
After rendering is complete, Mail opens and an email is created with the subject filled in and the movie attached.