In your project timeline, tap the clip you want to adjust.
At the bottom of the screen, scroll through the options and tap Opacity.
Drag the opacity slider left or right to control visibility. Moving it to the right makes the clip fully visible, while lowering it gradually adds transparency. You can use this to create fade effects, blend clips together, or let background elements show through.
If you reduce opacity all the way to the minimum, the screen turns completely black.