Open your phone’s Settings app
Tap Passwords & accounts or Accounts (wording may vary)
Select the account or service you want to change the phone number for (e.g., Google, Apple ID, carrier account, messaging app)
Choose Personal info or Contact info
Select Phone number
Choose Change phone number
Enter your new number
Complete any verification steps (OTP/SMS call)
Save or confirm the change
Update the phone number in other apps/services that use it (banking, email recovery, social media, authenticator apps)
Update 2FA/authenticator apps to the new number (or switch to authenticator codes)
Update any subscriptions or account recovery options using the old number
If your carrier number is changing, contact your mobile provider to port or update your line
Restart your phone after changes if prompted or if messages fail to verify