You can add your phone number associated with your device in your Google Account settings from your computer at myaccount.google.com/phone.
Your phone number is used when restoring your account, if you have forgotten the password for your google-account (SMS will be sent to the “linked” phone number), to personalize the displayed ads and in all Google services. Or just to log into Google services from your phone without a password.
After registering the number on the Internet, an SMS will be sent to your phone to confirm that the number belongs to you. For security reasons, the phone will periodically receive / send sms with the following text: “Google is checking the phone number of this device”.
Once the number is linked, go to Settings> Google> The phone number associated with the device.
I don't have a number on the screenshot, because this is not my main phone. After adding the number and confirming it, you can change the confirmation method here in the settings. Click on the item “Change the ways of contacting you” and select the methods of confirming the number (or disable confirmation altogether).
To summarize, why bind a phone number to a device:
- For communication with some Google services – two-step authorization (when entering gmail), calendar, Chrome browser, Google Pay and Google my business.
- To sign in to your Google account and regain access to it if you forgot your password. In this case, you will be logged in via SMS.
- To communicate with other users. Those. you can be found inside Google services by your phone number or specified email.
- To serve personalized ads based on your interests and search queries.
- For Google to further improve the quality of its services.