If you want to edit on your iOS device or share video on social media from your iPhone or iPad the video needs to be in your camera roll. However, videos you may want to share may not be there. If you shot the video on your own device then it will be in the camera roll. If it is video from someone else’s device or something taken on your camera or created on your computer you will want it there.
Whether you are using a Windows PC or an Apple Mac you will need iTunes for this. In the video tutorial below you will see how to do this. This includes videos you have in iPhoto.