After adding page numbers to the Word document, you may want to add a background to make the page numbers fancy. Please follow the steps below for details.
Step 1: Click the "Insert" tab from the ribbon;
Step 2: Click "Page Number" from the "Header&Footer" area;
Step 3: In the gallery, scroll through the options until you see the one you like;
Step 4: If there is nothing you like, you can always add a shape or an image from your computer or online.
Double click the footer area and click the "Insert" tab from the ribbon, then click "Online Pictures" (here we use the online image as the demo);
Step 5: In the search window, type the word for the image you want (e.g, star) and select one of the images you like;
Step 6: After selecting the image, resize it by dragging the corner to a proper size, then drag to the page number areas.
The image now is more likely in line with the page number;
Step 7: Click the "Layout Options" on the top-right cover of the image, and select "Behind Text" to send image behind of the text, then adjust the image position to make it comfortable to you.
Step 8: Save the document and the image is now the background of the page number.