Follow the steps in the support document you posted from to download the videos to a PC (assuming they were taken wit the iPhone and are in the Photos App). It explains exactly what you need to do to transfer them to a computer
You can't email large videos, as most email servers do not support large files attachments in email.
You can share them with other people by uploading to some location like a cloud storage service, a file sharing service such as weTransfer or even Youtube and then you can share a link to the videos over email.
https://wetransfer.com/explore/file-sharing
Share files and folders in iCloud Drive on iCloud.com - Apple Support
Share Files - Dropbox.com