Final answer:
Modifying the color palette of a document can be achieved by changing the theme colors, a feature available in word processing software like Microsoft Word and is independent of the document's orientation or Word version.
Step-by-step explanation:
To modify the color palette of a document, the statement that you can change the theme colors is true. In software such as Microsoft Word, theme colors are a set of colors used throughout your document to create a cohesive and professional look. You can access the theme colors option by navigating to the design tab, where you will find a variety of predefined color schemes to choose from. Additionally, you have the flexibility to customize your own color scheme to match your requirements. It's important to note that this functionality is not restricted by the version of Word you are using, nor by the orientation of the document (portrait or landscape).