OK, so this isn't exactly what Microsoft had in mind when it created Action Center for Windows 10 - it's meant for notifications, but Action Note keeps content from your created notes as entries there instead. OK, so you can argue that each note might be an action of sorts, i.e. something for you to do.

From the Store description:

Action Note is not just another note taking app. It integrates into your Action Center and enables the fastest access to all of your notes. Even with photos and across all your Windows 10 devices. Bring your productivity to the next level!

• Action Center integration
• Attachments
• Categorization and ordering
• Cross-device sync
• Offline support
• Personalization
• Beautiful design
• Scan QR codes

As usual, I gave this a whirl on the Lumia 950:

Notes are created and auto-saved, with titles, content, attachments, priority flags, and categorised by colour, pick the latter from the top right pick list. You can also pin a note to your Start screen, if appropriate.

Your notes appear in a collapsible list in Action Notes UWP itself, all laid out clearly, just tap to edit as needed; (right) Action Note appears prominently in Action Center, with a shortcut to create a new note and your top two action notes (here I've tapped on 'more' to expand the list).

There's not much on the hamburger menu, but you do get to browse notes you've archived away, plus you get to upgrade to the Pro version - with the cross-device sync, this is pretty much a 'must' once you're actually using the program for serious notetaking.

Plenty of configurability in Settings in terms of what appears in Action Center, plus you get to set defaults for new notes and also change what the live tile does.

You can grab Action Note UWP here. It's very slick and a way of taking OneNote-style freeform notetaking further into your phone's interface and making sure that you ever forget anything!