Start with a file you are allowed to save
Use a video you created, a download offered by the original creator, or another source that permits saving. If the platform already has an official download option, that is a sensible place to start. Saving a file does not give permission to repost it.
Downloads and Photos are different places
In Safari, a downloaded video usually goes to the location configured under Settings → Apps → Safari → Downloads. Depending on your settings and iOS version, this may be in iCloud Drive or On My iPhone. Open the Files app and look for the Downloads folder. Labels can vary by iOS version.
Move a compatible video into Photos
Open the downloaded video in Files, tap the Share button, and look for Save Video. If that option is available, the video is copied to Photos. Keep in mind that the Files copy may remain, so removing a duplicate later can free space.
If the video does not save
Check free storage, confirm that the download finished, and try opening the file in Files first. A file named .mp4 can still contain a codec your device does not support. Try an officially provided compatible version rather than changing the filename. Private or expired links will not become accessible by switching browsers.
SaveZuno is currently a website preview. Download and file-processing features are not connected yet.