How to Change the phone number on your gmail account

You can add, update, or remove phone numbers on your Google Account. Phone numbers are used for different reasons, and you have controls to manage how your numbers are used.

Add, update, or remove phone number

1. Sign in to the My Account "Phone" page.
2. From here you can:
   • Add a phone number: Under "Your phone numbers," select Add recovery phone. (We recommend that you add a recovery phone number if you haven't already.)
   • Change or delete your phone number: Next to your number, select Edit .
3. In the box that appears, follow the instructions.

Note: Changes to a phone number here take effect only for some Google services. Find out how to change your number for other Google services.

How phone numbers are used

As part of some Google services

Your phone number is connected to certain Google services that you've set up or used.

To see some services that use your phone number, check the My Account "Phone" page. To learn more or make changes, click or tap the service.

Other Google services that use phone numbers might not be listed on that page. You can change your number in certain services' settings, like the ones below:

• 2-Step Verification
• Calendar: Learn how phone numbers are used
• Chrome: Learn how phone numbers are used
• Google Payments
• Google My Business

Change how your number is used

To see your options for a certain service, go to its settings. If you need help, visit support.google.com.

Make sign-in & account recovery easier

You can use your phone number to:

• Sign in to your account in certain places. Learn how to sign in with your phone number.
• Get back into your account if you have trouble signing in. For example, you can get a text with a code to reset your password.

Better personalize ads you see

If "Ads Personalization" is turned on, your phone number might be used to show you more relevant ads.

Check if your number is used this way

1. Sign in to the My Account "Phone" page.
2. Next to "Usage," look for "Ads Personalization."

Change how your number is used

To start or stop getting personalized ads, change your ads settings. If "Ads Personalization" is off, your number won't be used to tailor ads.

You can keep "Ads Personalization" on for your Google Account, but stop your number from being used to tailor ads:

1. Sign in to the My Account "Phone" page.
2. Delete your phone number: Next to your number, select Edit   Remove number. Confirm your choice.
3. Add your number again as a recovery number. For detailed steps, go to the "Add, update, or remove phone number" section.

Improve your experience across Google

If "Across Google" is listed on your "Phone" page, this number can be used across Google services.

Check if your number is used this way

1. Sign in to the My Account "Phone" page.
2. Next to "Usage," look for "Across Google."

Change how your number is used

To remove this use but keep your number for account recovery and security:

1. Sign in to the My Account "Phone" page.
2. Delete your phone number: Next to your number, select Edit   Remove number. Confirm your choice.
3. Add your number again as a recovery number. For detailed steps, go to the "Add, update, or remove phone number" section.

Google doesn’t sell your personal information, including your phone number, to anyone. To learn more, visit privacy.google.com.

Important Remarks : All these content are from this official google answer part https://support.google.com/accounts/answer/3463280?hl=en&ref_topic=7188671

So you must read this on official google website the information mention here just for your information purpose only.