Take your photo and open it up.
Go to VIEW- SHOW MARKUP TOOL
Click on the SIGNATURE icon (located in center)
Write your signature on a piece of paper
Hold the paper up infront of the camera on your computer
It may take a couple of tries. When your signature “sits” on the line of the trackpad it will show up
That’s it! Now your signature is on the trackpad (on that specific computer)
You can drag and drop it to your photo