PrefixPlus - add the prefix app for iPhone and iPad

PrefixPlus allows you to add the prefix number to phone numbers in Contacts at once.
Phone numbers with the prefix number will not be replaced but added to contacts.
For example, if you set the number "+81" and the label "Call(JP)", contacts will be updated as follows.

[Before update]
Home: 03-1234-5678
Mobile: 090-1234-5678

[After update]
Home: 03-1234-5678
Mobile: 090-1234-5678
Call(JP) Home: +81-3-1234-5678
Call(JP) Mobile: +81-90-1234-5678


(Caution)
Be sure to back up contacts as security against accidents. For example, if you back up to iCloud, you can restore contacts at some point in the past.
Please note that you can add prefix numbers to contacts synchronized with local, iCloud, Gmail only.