Earlier today, Apple launched iOS 8.1 which introduced variety of brand-new functions to iOS and Yosemite. One of the expected features was TEXT Text Forwarding, which enables SMS messages obtained by your iPhone to be mirrored on your iPad or Mac running OS X Yosemite.
Numerous of our online forum participants had difficulty turning on the feature, as the required activation code would never ever show up on their Macs or iPads.
MacRumors viewers Michael composed in with this solution which requires an e-mail address to be triggered in iMessage:
… you have to have your email address turned on for iMessage on your iPhone in order to enable Text Forwarding. If you don’t, the numerical access code will not appear on your iPad or Mac during the arrangement process. When you allow your email address for iMessage (you just need to do this on your iPhone) the numerical accessibility codes look like anticipated. Once you have content message forwarding configuration you can disable your e-mail address once more in iMessage as it appears to simply be essential for the numeric accessibility code configuration step, not the real text forwarding itself.MacRumors was able
to validate this scenario and discovered that an e-mail address does indeed have to be active on your iPhone for the activation message to properly be sent out. In our screening, SMS messages were still received after the e-mail address was eliminated from iMessage. The readying to add your e-mail address to iMessage is under Settings- > Messages -> Send & Get. Keep in mind, you may have to wait a few minutes after adding an e-mail address prior to the activation code will send. [source]