A program that grants points for using Bing search, which users can redeem for gift cards, sweepstakes entries, or charitable donations.
For personal Microsoft accounts, Microsoft now says you can no longer add a phone number as a new security method. This method is being phased out. See official document here.
For account verification, you will need to use the other options - email, authenticator app and passkey.
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However, for Bing rewards verification, it is somewhat separate, though. Msft has now introduced an official alternative: “Verify with the Bing app.” You redeem from the Rewards website, select that option, scan the QR code with your phone, open/sign in to the Bing app, and enter the 6-digit code shown on the Rewards page. See details here https://support.microsoft.com/en-us/accounts-billing/rewards/use-qr-code-verification-to-redeem-microsoft-rewards