In iOS 17, when you ‌FaceTime‌ someone and they aren't able to answer, you can leave a video or audio message depending on the call method you used. If you are using ‌‌FaceTime‌‌ video, you can leave a video message, and if you are using ‌‌FaceTime‌‌ audio, you can leave an audio message.

All you have to do is ‌FaceTime‌ someone in the usual way. After a missed call, you'll see a "Record Video" option, which will allow you to create a message. After you've recorded one, you'll see a preview of your video, and the option to re-record if it didn't turn out well.

Here's how leaving a ‌FaceTime‌ message works on devices running iOS 17, using a missed video call as an example,

1. In ‌FaceTime‌, choose someone from your contacts to video call.
2. If they don't answer, tap Record Video.
3. Next, tap the Record button to record your message, then tap the Stop button when you're finished.
4. Tap Play to view the recorded message. If you're happy with it, tap the Send button, otherwise tap Cancel.

Once sent, the video message is in the ‌‌FaceTime‌‌ missed call log, where the person can watch the video and call you back.

Note that there is an option for people to save video messages to their Camera Roll, so keep that in mind when sending a video to someone.