The only problem with sending video as an email attachment is perhaps file size. Many email programs and/or service providers set limits. How big the file will be depends obviously on the length of the clip, but also on pixel resolution, the video format/codec, and the quality settings of the export. eg about 250MB for one minute of 720x576 best quality mpeg.
You will need to export only the section you want using 'File' >> 'Export movie' >> Video as ...' , and make sure you have 'Only export selected range' ticked om the export window. The method of marking a selection varies a bit between Magix versions -- in VPX you do left and right clicks in the band above the time markers on the timelines.
Added: Check also with family as to what file types they can use eg Magix video (,mvx file) would require a Magiv program to view and some people might not have Quicktime for viewing .mov files. Mpeg is probably a safe bet.