How to activate new device without access to other devices and SMS?
If the new iPhone is set up with the same Apple ID as your other devices you need to turn off Two Factor Authentication for the Apple ID.
If you're using iOS 10.3 or later:

Go to Settings &gt; [your name] &gt; Password &amp; Security.

Tap Turn Off Two-Factor Authentication.

Tap Continue.


If you're using iOS 10.2 or earlier:

Go to Settings &gt; iCloud.

Tap your Apple ID &gt; Password &amp; Security.

Tap Turn Off Two-Factor Authentication.

Tap Continue.