Open the Notes app on the source iPhone
Open the note you want to share
Tap the Share button
Choose Share Note if you want others to collaborate
Choose Send Copy if you want to send a static copy
Select Messages, Mail, AirDrop, or another sharing option
Enter the recipient’s Apple ID, phone number, or contact
Tap Send
On the other iPhone, open the received note or invitation
Tap Accept if sharing as a collaboration
Make sure both iPhones are signed in to Apple ID and connected to the internet