For example, Google can use the phone number to challenge people if they try to break into your account, and send you a verification code so that you can get into your account if you ever lose access.
Halimbawa, maaaring gamitin ng Google ang numero ng telepono upang hamunin ang mga tao kung sinusubukan nilang pasukin ang iyong account, at maaari ka nitong padalhan ng verification code upang makapasok ka sa iyong account kung sakaling mawalan ka ng access.