1. If the color contrast between the foreground and the background is great, you can use the color range to extract it.
2. If there is a channel with clear black and white, you can use the channel method to key it.
3. If the boundary between foreground and background is obvious, you can use the magic wand tool to deal with it.
4. If the boundary between foreground and background is not obvious, you can use the pen tool to pinch it.
5. If the boundary is complex, such as hair, you can use Knockout2 filter to extract it.
wait.