Download and install iTunes, connect iPhone to your computer, and then open iTunes.
2. When iTunes successfully recognizes the iPhone, please click "Movies" in the upper left corner of the iTunes interface, and all imported movies in the iTunes music library will be displayed on the right side of the interface. Import here refers to importing the movie files on the local computer into the movie database of iTunes.
3. Then click "File" in the iTunes menu bar. In the pop-up drop-down menu, you can see two options: "Add file to resource pool" and "Add folder to resource pool".
4. After importing, you can select iPhone under the left device column, and then click the video option on the right interface. In the video operation interface, you can see that there are imported movie files under the synchronized movie column. If you want to synchronize this movie, please tick √ before "Synchronize Movie" and the imported movie file, and finally click "Synchronize" below.