I guess when you say "there are obvious picture marks around the handwriting, it doesn't look like a real person's handwritten signature", you mean that if you print it as a photo, if you can hide the part except the text, it's like pulling the signature out of the picture and putting it in the position of the signature item in the form, it won't cover the nearby grid.

Look at this operation:

1. Scan with the highest level scanner, which is clearer. Before saving, trim the picture, keep the signature area and save it as a picture format;

2. After inserting the picture into EXCEL, click to select the picture, and a "Format" toolset will appear on the far right side of the toolbar above;

3. In the lower left corner of the formatting toolset, there is a "recolor" drop-down menu. Click the drop-down menu and select "Set Transparent Color" at the bottom. At this time, a pen with an arrow appears in the mouse cursor pattern. Use this pen to check the blank space of the inserted picture;

4. After the above operations, only the black signature is left in the inserted signature picture, and the cells originally covered by the picture are also exposed;

5. Then drag the picture to the right place and print it out to see the effect.

6. If the scanned document quality is not high, please use image processing tools to process it first, and then insert excel.

In addition, I use excel2007, and the function changes of other versions are unknown.