Apple Notes
Apple Notes is the standard note taking app used by Apple on all of their devices. The Functionality is as follows
Make notes
Sync the notes across devices
Siri can automatically write to it by speech 
Integrates with Apple Intelligence 
Here are the great open source alternatives to Apple Notes that even have more functionality than you could ever think a note taking app could have. 

1. Joplin
Documentation Page: Joplin