I had a client ring me and say he had swapped iPhones and the telco was unable to get his notes across.
I asked if he had turned on iCloud – he said he did not bother as iCloud was not important. However it is important and turning on iCloud on his old iPhone and new IPhone would have resulted in his notes being restored.
iCloud on Apple devices will sync amongst others:
and most important – Find my iPhone
More details can be found on iCloud here: iCloud
This also makes it easier when you upgrade to a new iPhone and remember have a good password with your Apple ID and turn on 2 factor authentication.