I am a big fan of Two Factor Authentication.  If you are not familiar with two factor authentication, there is a good explanation here.  I have enabled  Two Factor authentication pretty much on any account I have that supports it.
Many Two Factor implementations use the Google Authenticator app to provide the authentication code.  Setting up  the authenticator is easy, you generally scan a QR code, and then enter the code to confirm the setup.
One of the difficulties when using Two Factor authentication is setting up the Authenticator app on a new or additional device. Â When you initially set up Two Factor authentication you are presented with a QR Code that is scanned by the app to automatically configure the account. Â Typically to set up another device you have to invalidate the original configuration, and sometimes even disable and then re-enable Two Factor Authentication altogether.
Recently listening to an episode of This Week in Google they shared a tip so simple I don’t know why I never thought of it. Â When you first enable Two Factor authentication for a given account download the QR Code image and save it somewhere securely. Â Since I use Lastpass as a password manager I create a secure note which allows me to securely upload and save the QR code image. Â Configuring the Authenticator App on an additional or new device is as simple as opening up the secure note and scanning the bar code.