When an empty Text note is created, a note type switcher will appear below the inline Title. Apart from changing the note type, it's also possible to apply a template:

•  Markdown and  Canvas switch the note to that type in one click.
•  Code lists the scripting notes (Custom CSS, Widget and Backend script), then the enabled code languages.
•  Collection and Template list the collections and the templates.
•  All types displays the same menu as Insert note after in the Note tree contextual menu, with every note type and template.

Typing while the  Code,  Template or  All types menu is open narrows it down to the matching entries.

The switcher will disappear as soon as a text is entered.