How to watermark or personalize a picture?

Taking ps as an example, the method of adding personalized signature to pictures is:

1, write a personalized signature on white paper.

2. Take photos with a camera.

3. Enter the computer.

4. Open the picture in PS.

5. Select-Color Range-Click the color of the text-Adjust the tolerance-OK-Copy-Paste.

6. Open the image to be watermarked.

7. Put the personalized signature into the image.

8. Adjust the size and position.

9 Save after merging layers.