Fullscreen desktop modals command the entire screen, focusing users' attention on crucial tasks or information. Much like popup modals, they block out underlying content until users take action. Often resembling a new page, these modals are typically used for tasks like logging in, registering an account, showing terms and conditions, or delivering feedback and error messages. They can also handle more complex activities like processing payments or guiding users through multi-step forms.

While effective in grabbing attention and minimizing distractions, these modals must be used judiciously. Overuse can disrupt the user experience, causing more annoyance than engagement.