The same number information in Apple's mobile phone address book overlaps. What happened?

The same contact has been added repeatedly. Click merge and repeat it many times.

Click Merge and repeat several times until there are no duplicate business card locations in the merge. After the above operation on the mac, if your mobile phone and the mac are the same account and icloud is turned on, it will be synchronized to the mobile phone soon. Is it fast and convenient, at least much more convenient than on a mobile phone? In addition, some friends may think that the same effect can be achieved through xx address book software. What I want to say is that when you use xx address book, you will find that it may not meet your needs or this kind of software is not easy to use. Most importantly, if it is not official software, it will be hacked and your information will be leaked. Therefore, it is suggested that if you happen to have a mac around you, using a native app is definitely safer than a third party.