Hi Arystarque,
Welcome to the Apple Support Communities!
I understand that you would like to sync notes across your devices. The easiest way to accomplish this is to use iCloud for syncing. The attached iPhone User Guide below (page 108) discusses how to set up iCloud notes on your iPhone.
https://manuals.info.apple.com/MANUALS/1000/MA1565/en_US/iphone_user_guide.pdf
Notes at a glance
Type notes on iPhone, and iCloud automatically makes them available on your other iOS devices and Mac computers. You can also read and create notes in other accounts, such as Gmail or Yahoo!.
See your notes on your other devices. If you use an icloud.com, me.com, or mac.com email address for iCloud, go to Settings > iCloud, then turn on Notes. If you use Gmail or another IMAP account for iCloud, go to Settings > Mail, Contacts, Calendars, then turn on Notes for the account. Your notes appear in Notes on all your other iOS devices and Mac computers that use the same Apple ID.
For information on how to set up iCloud for notes on your Mac, please refer to the next attached article.
Notes Help
Add an account to use with Notes: Choose Notes > Add Account, select an account type such as iCloud, then enter your account information. Make sure the Notes checkbox is selected for the account.
Once the same iCloud account has been set up on both devices, any notes in iCloud notes will automatically sync between your iOS devices and your Mac.
Best regards
