How do I make a child account on an Xbox an adult account

I can't remember 100% but I am sure whoever set up the child account can change it. Like if you made an adult account on the xbox before making the child account that adult account can change wether the child account is a child account or and adult one.
I will just test this out myself now and post how it went

You need to contact Microsoft and submit your ID card photo to prove you are an adult

You can change the birthdate of a child account:

1. Using the parent's Microsoft account, sign in to your account on
https://family.microsoft.com.

2. At the bottom of the Your Family page, select Manage my child's profile info.

3. In the Manage permissions page of the child's account that you want to change, at the right, select
Edit this child's personal info and then follow the instructions.

Microsoft is in the process of Reimagining the family experience so some things may be different.

Hi,Camryn ! I'm Luis, a fellow Xbox Gamer . Thanks for reaching us out here.

Unfortunately you can not do that

You need to wait until the account "turns" into an adult by itself according to the initial birth date. This is to avoid actual childs changing the birth date.

It is very important to set the birth date right the first time

Hi Frost,

Thank you for posting on the Xbox forums. Unfortunately it is not possible to force a child account to become an adult account on Xbox Live. Changing the Microsoft Account profile age will not change the account and give adult permissions to the child account.
An adult account would need to be set up separately by the parent and add the child account to a Microsoft Family group and then manage the child account while logged into the parent account to allow adult permissions on a child account. A child account cannot
make any Xbox Live privacy settings without an adult account. If you already have an adult account, sign into
family.microsoft.com. For further instructions on how to set up a family group and then manage the child account's privacy settings, please read the following support articles:

• Add members to your family group
• Xbox One online safety and privacy settings for parents and kids

The link provided by tez bomb is helpful setting up content restrictions directly on the Xbox One console, after you've already set up your Microsoft
Family.

I hope this helps!