In depends of what you want to do. But for extended development you should get familiar with the Mendix Model Pro because it is the more professional tool.
You can get a default login page if you set the security to production in the modeler.
Check https://docs.mendix.com/studio/settings-security for details about setting security in studio.
Publishing will enable security, else use studio pro like Gerrit says.
The login page is a default login page. styling this page requires Studio Pro