Last year, Google changed the name of the wireless operator service from Project Fi to Google Fi, opened up to several Android devices and launched a beta application for iPhone ($ 1000 on Amazon) users.
If you have signed up for Google Fi with an iPhone or are considering it, you need to know about setting up an Apple product on Google's wireless service.
Compatible iPhone models
According to a Google Fi support page, the following iPhone models work with Fi:
It's a good idea to double-click that your specific iPhone model will work on Fi with Google's compatibility check tool.
What You Need
In addition to an iPhone that is compatible with Google Fi's network, you need:
You can order a free SIM card from Google Fi either through the mobile app or through the Google Fi store.
After receiving your Fi SIM card, turn off your iPhone, insert the SIM card and turn on the phone. Then open the Google Fi app. The app will ask you to log in with your Google Account and then go through the installation process, which involves changing the APN settings on the iPhone so that it knows which network to connect to and enables the ability to send and receive MMS messages .
The Fi app shows you what you need to enter and allows you to copy the URL that goes into the MMSC field. Press the button to copy the URL. If you enter errors, you cannot send or receive picture messages.
With the URL copied, leave the Fi app and go to Settings > Cellular > Cellular Data Network . Those on IOS 11 must go to Settings > Cellular > Cellular Data Options > Cellular Data Network .
in the three different text fields labeled APN, type "h2g2" – without quotation marks.
In the MMSC field, paste the URL you copied from the Fi app. If you did not copy it, either go back to the app and do it now, or copy and paste this "http://fi.g.co/mms/wapenc" – again, without quotes.  Return to the Google Fi app and go through the last screens until you find out that you are restarting the phone. When it goes back, open the Google Fi app again and exit the installation process. Your iPhone should now connect and work on Google Fi without any problems.
Of course, there are some precautions. Google Fi iPhone users will unfortunately miss some features that those using an official Fi phone may use.
Visual voicemail does not work right now, nor is the ability to switch between networks or use Wi-Fi calling and subtitling. iPhone users can only use the hotspot feature in the United States.
With inability to switch between networks, iPhone users lock in with T-Mobile's network for their Fi experience.