You’re using GitHub - valentine195/obsidian-admonition: Adds admonition block-styled content to Obsidian.md and are reporting in the wrong place.
Anyway, for most cases, you no longer need the above plugin as you can use the recently shipped built-in callouts Use callouts - Obsidian Help
Once you start using that, you can simply do:
> [!NOTE] Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla et euismod nulla.
And you will get no titlebar:
