Downloading on iPhone or iPad
It is possible to download video and audio files from Videvo to iPhones or iPads, providing that you are running iOS 13.0 or later, and downloading using Safari.
You can choose to store your downloads either in iCloud, or on your device, by going to Settings > Safari > Downloads. You can also choose to store to Dropbox or any other file sharing apps you may have installed.
If you are downloading on an older version of iOS, downloading natively to the iOS file structure will not work, and you will need a third-party file sharing app, such as Dropbox to store the files.