iPhone photos and videos of the beautiful scenery in Japan.

Tap a “+” button under the video track.

Tap “Text”.

Input the text , then tap “Done” to finish.

Slide a menu bar on the bottom until “A” shaped button, then tap it.

You can change a line weight by a slider or triangle shaped button.
I think 3.0 is good.
You can change the color of the line tapping a rectangle on the right.

Slide a menu bar until check button appears, then tap it to finish.