This is because the shading color is set in the word document. You can set it to delete the shadow of the printed document by the following steps, as shown below:

1 first open a word document, and you can see that there is a gray background under the text, so that the printed file will have a shadow:

2. Then select this paragraph, find "Shading" in the start menu bar above, click the triangle next to it to open shading, and select the following "No Color" in the theme color:

3. At this time, if you look at the text in the document, you can see that there is no shadow in the text background, so that the printed file will not have shadow: