Open the VLC app on your iPhone
Play the video you want to watch
Tap the screen to show the playback controls
Tap the subtitle icon or speech bubble icon
Select the subtitle file if it is already available
If needed, import the subtitle file into VLC first
Make sure the subtitle file has the same name as the video file
Place the subtitle file in the same folder as the video
If subtitles do not appear, go to the audio/subtitle settings
Choose the correct subtitle track
Adjust subtitle delay if the timing is off
Restart the video if the subtitles still do not load