Facebook is all about networking and sharing, and videos are no exception. Depending on the video and your intended result, you can show or send your friend a video in several ways. Give her the link in chat or on her Timeline if the video is posted on the Internet. If the video isn't online, upload a short video directly to her. For videos posted on Facebook, tag her in the video or its comments section.
Share the Link
For sites that don't provide simple link forwarding, copy the URL of the Web page containing the video and paste it into a Facebook chat message. When the preview appears, remove the pasted URL, and she'll still see the video link when you send the message. The same goes for posting a video on her Timeline; after the preview appears, you can safely delete the URL without removing the link.
Tag, You're It!
When you tag a friend in a Facebook post or comment, the site notifies her. If someone else posted the video to Facebook, tag her in the comment section by typing out her name and clicking her picture when it appears. After you submit your comment, Facebook notifies your friend of the post. Your friend may not be able to see the post if the original poster has his privacy set to something other than "Public." If they're mutual friends, she's more likely to have access.
Send an Attachment
If the video is on your computer instead of on the Internet somewhere, send it as an attachment. From within a Facebook chat window, click the gear icon to bring up the Options menu. Choose "Add Files" and select the video with the new Windows Explorer window. Give Facebook time to upload the video. Your friend has to download the video to watch it. Share the video as an attachment on her Timeline by selecting "Photo/Video" in the posting window and then clicking the white box with a plus sign to select the video using Windows Explorer. All attachments must be under 25MB. You can upload videos in a number of formats including MP4, AVI and WMV. Facebook publishes a list of every accepted video format.
Within Video Viewer
When viewed from the Video section of your or a friend's Facebook photos, videos display in a window similar to the picture viewer. Click the "Tag a Friend" button to do just that. Enter her name in the "Who Were You With?" text field and select her name when it shows up. This has the same effect as tagging her in the video's comments, only you're not writing a new comment just to tag her.