It's about marketability of your act, your image, your performance. A professional photo shoot is a must, and a bio and portfolio helps. They want to sign and sell a package - not just the music (unless it's REALLY mind-blowingly good). Before your Demo Submission - ask yourself what YOU would like to see, as the owner of your own record label. Which artist would YOU want to sign, if YOU had to make the financial decisions? At the very least, get a website, or update your social media accounts to reflect as much about yourself, and why you are the logical choice for a major signing.