1. First, use the trimming tool or pen tool to fill the edge of the door frame with black according to its shape and outline, and use the matting tool to remove the interior of the door frame, so that nothing inside the door frame will appear in the final picture.

2. Secondly, adjust the size and thickness of the door frame with adjustment tools to facilitate the insertion angle. Use the wand tool or the selection tool to select the corner area of the door frame.

3. Finally, choose the corner insertion tool, add corner insertion effect in the corner area of the door frame, modify the adjustment effect, use smear tool or eraser tool to deal with the unnecessary position, merge the door frame with the corner insertion position, and save and export the final image.