Set the Default Communication Method in IOS 10 for Easier Access to Numbers
If you have a contact on your phone that has multiple email addresses or phone numbers, for example for work, home, or a mobile phone, it’s easy to forget which number pops up at the top when you search. How-To Geek indicates that you can set a default number which will make this easier.
The process is a little confusing here. If you have multiple contact methods specified, the first time you tap the blue icon in the new contacts box in iOS 10, be it the message, call, or email icon, iOS will ask you which one you want to use. The one you choose will become the default.
When you select one of these, it also initiates a call, text message, or email, so be prepared to cancel it if you’re just trying to set the default. Once you select the default, it will be automatically filled in when you create a new message. Changing that to something like an email address where you can have multiple addresses for the same person is extremely helpful, especially if iOS insists on using iCloud email, which they never default to someone else. Go to the How-To Geek site for more information, including setting Siri to work properly and a list of favorites.
How to Set the Preferred Contact Method for Contacts in iOS 10 | How-To Geek