Set IPhone to Use Speakerphone by Default
If you are on a long trip or simply prefer to use the speakerphone, it will be difficult to set it up every time you answer a call. On iPhones, the accessibility options allow you to set this as the default.
This option is another feature that everyone benefits from. To set your iPhone to always respond to the speaker:
- Go to Settings> General Accessibility.
- Click Call Audio Routing in the Interaction section.
- Change the setting from Automatic to Speaker.
Your iPhone will now always ring in speaker mode. You can still switch back to the handset or Bluetooth, but the speakerphone will be used by default first.
How to set up automatic activation of the speakerphone mode when making calls on iPhone | OS X Daily