Bitwarden is a free online password and secure note manager (that I'd not previously heard of, but it looks excellent) - and despite no official support, there's a full third party UWP client, named Bytewarden, for Windows 10 Mobile. Note/password syncing is instantaneous to the cloud, very impressive, you can enter or edit information on the web on your desktop, or via a client on any platform, and all data is available everywhere.

From the Store description for Bytewarden:

This is an unofficial open source client for the bitwarden password manager. This client is based on the original bitwarden mobile client with added support for Windows 10, Windows 10 mobile, Windows 10 S and Xbox One.

This client includes support for:

• Using Windows Hello to unlock the vault (Fingerprint, Face or IRIS)
• Using a PIN to lock/unlock the vault
• Offline read support after authenticating
• Using the YubiKey OTP for 2FA
• Using your devices camera to read 2FA QR codes

All of the source code and more information is available here: 

Some example screens of this in use:

The 'bitwarden' account is server-side and maintained for free, at least for individuals; (right) the Bytewarden client masterminds login, including Windows Hello on phones, tablets and laptops.

As usual with password managers, it's easy to sort entries, search them, add and edit things as needed. Anything changed immediately gets synced online. The interface is clear and colourful, though parts of the UI are HTML from the Bitwarden web site and so UI elements change. 

I do have some quibbles at the moment though. As a hybrid part local, part online client app, it's far to easy to exit the UWP app by pressing 'Back' in the wrong place. Plus I saw sync glitches, and you can one-tap copy information from some fields but not others. Still, it's a work in progress, eh?

You can grab Bytewarden UWP in the Store here. It's open source (here) and free.