1. Open the YouTube app on your iPhone and find the video you want to download.
  2. Tap the Share button located under the video.
  3. Select the “Copy Link” option.
  4. Open the Documents by Readdle app, which is a free third-party app that allows you to download videos from YouTube.
  5. Tap the browser icon located in the bottom right corner of the screen.
  6. In the browser, go to savefrom.net.
  7. Paste the link you copied from YouTube into the search bar on the savefrom.net website.
  8. Select the “Download” button next to the video quality you want to download.
  9. Once the video has finished downloading, tap on the “Downloads” icon in the bottom right corner of the screen.
  10. Select the video you just downloaded, then tap the “Share” button in the top right corner of the screen.
  11. Select the “Save to Camera Roll” option. The video will now be saved to your iPhone’s camera roll.

Note: please note that some third-party apps that allow you to download videos from YouTube may not be available in all countries and downloading videos from YouTube may violate the terms of service.