If you use the Notes app on your iPhone or iPad regularly, Siri makes it easy to access them at any time by just asking for them. Not only can you pull up notes from certain time frames, you can also ask Siri to show you notes about specific things.
How to view notes in the Notes app for iPhone and iPad with Siri
Press and hold the Home button on your iPhone or iPad to launch Siri.
Say something like "Show me my notes." or "Show me notes from today." or "Show me notes about iMore." — just replace iMore with the keyboard you want Siri to look for.
Siri will present you with a list of notes in the Notes app that match the description. Tap on the one you want to open it.