1. Open the signed picture, click the color range under the selection menu, suck the color of the signature with a straw, and adjust the color tolerance appropriately. When the preview is clear, you can be sure.

2. Determine the selected area where the signature appears in the image, press "Ctrl+J" to copy the signature to the new layer, and close the eyes of the original layer to see the effect. If you are satisfied, you can delete the original layer and leave only the duplicate layer. If you are not satisfied, you can try again many times.

Save it in PSD format, open this file when you use it, and drag the signature directly to other pictures.