There are a couple of options for digitizing your scrapbook layouts. The easiest one is taking a picture of your layout - but you need to be very careful with the lighting and the angle of the picture.
If you need something high quality for archiving or contests, consider scanning your layouts. If you only have access to a regular Letter/A4 size scanner, which is smaller than the layout size, you can use the following instructions for scanning the layout.
You can use 2 scans or 4 scans for a scrapbook page. Using 2 scans is faster, but you might lose some of the bottom part of the design since the scanner is usually shorter than 12”.