The "dropper" you are likely thinking of is a feature used in image editing software like Photoshop or GIMP. It allows you to select a color from an image by clicking on it and then use that color for other elements.
Word does not have an image editing function like this.
If you are trying to use a specific color in your document, you can use the "Color" options within Word's "Font" or "Paragraph" settings.
Let me know if you have any other questions!