Tina,
You can make maximized the permanent setting for Microsoft Edge by going to the icon on the desktop, pressing alt-enter for properties, then tabbing past the shortcut option to "Run as..." Use the arrow keys to find maximize and press the spacebar. Then tab to Apply. You'll be told you can't because you need administrative rights, but press spacebar again and you'll get them! Then press spacebar on Apply again, then tab to Okay.