Following are the steps to remove the black background in Capcut:
1. Open the Capcut application on the smartphone,
2. Select the "New project" button,
3. Select the video that will be the background video from an image or video that has a black background,
4. Select the "Overlays" option,
5. Select the "Add overlay" option, then select an image or video with the desired black background,
6. Then select the "Blend" option,
7. In the "Blend" option, select the "Filter" option,
8. Done.