Does iPad 2018 support instant notes?

Yes. See the following from Use Notes on your iPhone, iPad, and iPod touch - Apple Support

With iPad Pro and iPad (6th generation), you can use an Apple Pencil to create an instant note from the Lock screen or pick up where you left off on your last note. To change these settings, go to Settings > Notes, tap Access Notes from the Lock Screen, and choose an option.

Tap the Lock Screen with your Apple Pencil and create your note. Whatever you create is automatically saved in Notes.