how to change my number on here

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.

https://support.microsoft.com/accounts-billing/manage/microsoft-to-stop-sending-sms-codes-for-personal-accounts

Are you hoping to update the contact method to receive the 2FA verification?

If so, you go to https://account.live.com > Security > Manage how I sign in. And you will need to use email, the authentication app, or passkey.

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If you cannot sign in at all, on the page asking for the code, look for an option like “Show more verification methods” to see if you have a backup (e.g., a phone number or alternate email).

If you don’t have access to any of the options listed, select “I don’t have any of these.” This will begin the recovery process. As part of that process, Microsoft will let you add new contact information — but only after a 30-day waiting period.

This 30-day delay is intentional. It’s a security safeguard designed to protect users in case someone else tries to hijack their account by changing recovery info. The wait gives the rightful owner time to notice and stop unauthorized changes.

Unfortunately, this policy cannot be bypassed. Microsoft explains it further here.

https://support.microsoft.com/account-billing/-your-security-info-change-is-still-pending-or-you-can-t-access-this-site-right-now-microsoft-account-message-cbd0f64f-02d9-45d2-90c3-2375e5a72e52#:~:text=While%20we%20understand%20this%2030,phone%20number%20or%20email%20address.