Use Tags and Smart Folders in Notes on your iPhone and iPad - Apple Support

Use tags to quickly categorize your notes so you can easily find them later. Just add one or more tags — like #work or #shopping — anywhere in any note. You can also use tags together with existing folders to search and filter your notes across multiple folders.

Get started with Notes on iPad - Apple Support (TM)

Organize your reminders with tags on iPhone - Apple Support (TM)

Take notes on iPod touch - Apple Support (MY)

iOS and iPadOS 15: The MacStories Review - MacStories - Part 14

Use Tags and Smart Folders in Notes on your iPhone and iPad - Apple Support

How to use Smart Folders in iOS 15 and iPadOS 15 – Apple World Today

macOS Monterey: The MacStories Review - MacStories - Part 4

A Closer Look at Apple Notes's Smart Folders – The Sweet Setup

How To Quickly Organize iPhone Notes Using Tags & Smart Folders

How To Create Smart Folders and Tags in the Notes App