Applies to: School Loop Standard
You can absolutely put a link to the login page wherever you need. Just add a text module using the plus icons on your page, and there you can add an image or text with a link to the login page.
Another idea is to have one of the badges (near the top of some designs) link to your login page.
To link any text or image, just click it once and check the toolbar at the top. The chain icon lets you link.