iPhone & iPad
Save YouTube videos to an iPhone or iPad straight from Safari, then move them into Photos.
iOS 13 or later.
How it works
Open the video, tap Share, then Copy link.
Open savetomp4.net in Safari, paste the link, choose 720p or 1080p and tap Convert.
Tap Download and confirm. Open Files → Downloads, tap the video, then Share → Save Video to add it to Photos.
What you get
Apple doesn't allow downloader apps in the App Store. A web page in Safari is the dependable route.
Since iOS 13, Safari has a built-in download manager. That's all this needs.
Downloads go to Files → Downloads, on your iPhone or in iCloud Drive.
One tap on Share → Save Video puts the MP4 in your camera roll.
H.264 video with AAC sound, the format iOS plays natively.
Same steps on iPadOS, with more room for the Files app beside Safari.
Once it's in Files or Photos you can AirDrop it to a Mac or another iPhone.
Specs
Safari shows a small arrow in the address bar while a download runs. Tap it to see the file, or open the Files app and look in Downloads. If you can't find the folder, check Settings → Safari → Downloads to see where Safari saves things.
Videos in Files don't appear in the Photos app until you save them there. Open the video, tap the Share icon and choose Save Video.
Occasionally Safari plays the file in a new tab. Tap the Share icon and choose Save to Files, or press and hold the Download button and pick Download Linked File.
Questions
No. Safari's own download manager handles it.
To the Files app, in the Downloads folder. From there you can save them to Photos.
Open it in Files, tap Share, then Save Video.
Yes. Chrome saves the file to its own Downloads list and to the Files app.
HD video is large. Try 720p or 480p, or clear space in Settings → General → iPhone Storage.
More tools
Ko-fi
SaveToMP4 has no accounts and no paywall. If it saved you time, a coffee helps cover the servers.