CloudNotes is a notes editor that syncs with the Notes app (https://github.com/nextcloud/notes/releases) on your server.
Once you have logged in to your server, all notes will be kept in sync between devices and also the web interface. Optionally supports sync on startup.
You can create and delete notes directly on the device. Edit as plain text or use markdown for rich formatting. Notes can be copied or exported to other apps or services in several formats.
If you have a sync client (optional) installed on your desktop computer all notes will be there too, and can be edited with any text editor.