How do you find your Microsoft account number?

You can find how to do that here https://support.microsoft.com/en-us/help/12407/microsoft-account-change-email-phone-number

How to find your Microsoft account
Applies to: Microsoft account

If you got the error message That Microsoft account does not exist, this article can help you find it.

How to find your Microsoft account using your security information.

1. Look up your username using your security contact phone number or email address.
2. Request a security code to be sent to the phone number or email you used.
3. Enter the code and select Next.
4. When you see the account you're looking for, select Sign in.

If you haven’t set up or don’t have access to your security contact information, you can try looking for your Microsoft account username within the product or services that you are using.

How to find your Microsoft account username in the product or service you use

For the protection of your account, we have strict policies on how our advocates can help you with your account. Microsoft Support advocates are unable to provide account information without proper validation, but there are places you can look within the
products themselves.

Have you ever set up an alternate email address for the account you want to sign in, such as @outlook.com, @gmail.com, or @live.com? If so, try that.

Hey Klevis_,

Did you forget the details to your Microsoft account or your PSN account? If it was your Microsoft account and you still remember the email which you associated with it?

How to find your Microsoft account using your security information.

1. Look up your username using your security contact phone number or email address.
2. Request a security code to be sent to the phone number or email you used.
3. Enter the code and select Next.
4. When you see the account you're looking for, select Sign in.

For a more detailed guide you can go to https://support.microsoft.com/en-us/help/13811/microsoft-account-how-to-find

I hope this helps you!

You should be able to change it at
http://account.live.com

I gave you the link. Just go to your info under your account and it gives you the options for changing information on your account.