How to bring up highlight selection in PS?

1, first open the PS software, and then open the picture to be processed in PS.

2. Next, press the shortcut key "Ctrl+j" to copy the background layer, and the subsequent operations will be carried out on the copied layer.

3. Next, select "Channel" at the bottom of the page.

4. Next, press and hold the "Ctrl" key, click the RGB channel with the left mouse button, and then highlight the selected area, and then you can operate the highlighted area.