The next screen offers a choice of how to invite your Guardian to join your Vault: either “Send a message” or “Scan a code.” “Send a message” allows you to share an invitation link from an installed app on your phone to an app on the Guardian’s device. The sharing process is standard, and the options that you see will depend on what is installed on your phone. Just hit “Share Message” or Copy/Paste the invite link to the messenger or communication method of your choice, and send it to the new Guardian or to your spare device.