How do I prevent my children from using my XBOX account?

As others have suggested a passkey is the best way to go - and is what I use here

Hi Kujawafamily,

Thank you for posting on the Xbox forums. I'd be happy to help.

You can view the sign in activity of the Gamertag associated with your Microsoft Account from the
Recent Activity tab on account.microsoft.com. It will show device or app specific info and I believe it also has the time when signed in as well.

I recommend setting up your account on the Xbox with more sign in security like a passkey or locking it down with the password. Just sign in with your account on the Xbox and open the Settings. Then on Account, select the first option "Sign-in, security,
& passkey", then "Change my sign-in & security preferences". Select Ask for my passkey, which will make you create a 6 digit passkey for signing in, changing settings, or making purchases. You can also select Lock it down to require the account's password
for the same things the passkey secures.

I hope this helps!

Kujawafamily,

You should put a passkey on your account. https://support.xbox.com/en-US/my-account/security/create-xbox-one-passkey

Here’s just a few benefits of having a passkey on your account:

• A passkey protects against a child signing in as the parent and overriding parental controls. A personal passkey prevents a child from simply clicking on the parent’s picture, signing in as the parent, and changing the child’s otherwise
  parentally controlled settings.
• A passkey helps to prevent unapproved charges. You can choose to require a passkey to make any purchase on Xbox Live. Setting a passkey helps prevent children from making unapproved purchases.
• A passkey allows the parent to grant content exceptions. The only way for a parent to override a content limitation is by entering his or her personal passkey, so it’s easier to manage what content your children can see on your console.

When on your account you should be able to go into settings and on your account there should he an option to lock it down so nobody can get on it without password

I would change the log in information on the parent account meaning the password. Enable two step verification so that way your mobile device gets notified and has to approve log in. Put the authenticator app on your mobile device from your app store for
the device...ios..android. I would suggest a passkey if you want to use that route and that can be done from the xbox. Two step verification would be through

Login.live.com, type this in browser to go to your Microsoft account