Twitter doesn't let you save videos directly from its app on iPhone. The native Share menu has no Save Video option for someone else's tweet. The workaround is to copy the link, paste it into a downloader, and save the MP4 to Files or Photos. Below: the exact steps, plus how to bypass common iOS quirks.
Step 1 — Copy the tweet link in the X app or Safari
Open the tweet you want to save. Tap the Share icon (paper plane in the X app, arrow box in Safari). Choose Copy link. The URL is now on your clipboard — it should look like https://x.com/username/status/....
Step 2 — Paste the link on TwitDownloader
Open this site in Safari (or Chrome). Tap the input box on the homepage. Hold and pick Paste. Hit Download. Within a couple of seconds you'll see preview thumbnails and quality options.
Step 3 — Save the MP4 to Files or Photos
Tap the HD button. Safari downloads the MP4. Tap the small download icon (next to the address bar) → tap the file → Share icon → Save Video to put it in Photos, or Save to Files for the Files app. Either way it's now offline.
Common iPhone gotchas
If Save Video is missing from the share sheet, you opened the file in the wrong app — open the download from Files first. If Safari blocks the download, check Settings → Safari → Downloads and make sure storage is set to On My iPhone or iCloud Drive. If the file plays inline instead of saving, hold the play button and choose Save to Files.
Want just the audio or a GIF?
Same steps, different tool. The Twitter to MP3 converter strips audio. The GIF downloader handles Twitter's silent-MP4 GIFs. The image downloader grabs original-resolution photos.