How to change the restriction of account ?

What are the issues you are seeing?

Once the age listed on the account is 18 the account should automatically promote to an adult account. The age on your xbox account is permanent so if it was ever changed on account.microsoft.com it would not change the xbox account.

Check this
Online Safety Settings troubleshooting page.

The procedure for changing Gamerpics is here :
https://support.xbox.com/en-US/my-account/manage-gamertag-and-profile/change-gamerpic-on-xbox-one

The only restrictions mentioned are that a child's account cannot use a custom Gamerpic. There are no restrictions on how often you can change the Pic.

I suggest you to check this support link:
support.xbox.com/.../error-child-trying-to-access-settings

If the purchase is coming from the restricted account(s) then there should be a prompt asking for the password/pass code for the parent account of the child(ren)'s account. (That's how it is on my console.) After entering the password/pass code, you will
be allowed to make purchases on the restricted account for a limited time. Assuming this didn't happen for you, there's another way. You'd have to change the child(ren)'s account permissions, allowing them to make purchases. After the purchases, you may change
the permissions back, restricting the child(ren)'s account once again.

Hi, I hope you're doing great out there.

I'm Wille, an Independent advisor and I am here to help you with your concern.

Your date of birth is correct in the link below:

https://account.microsoft.com/profile

If yes, what would it be?

If you are the wrong age, and you are over 18, you can try the following:

If you are in a family group, simply ask the Adult who manages the family to change your age at https://account.microsoft.com/family.

If you're not in a family group, someone close to you who has an account with an adult profile can create a family group and add your account as a child and change your date of birth. To do so, you can follow the instructions in the link below:

https://support.microsoft.com/en-us/account-bil...

1. Basicaly, using the adult microsoft account, sign in to your account at https://account.microsoft.com/family

2. Scroll to the bottom of the Your Family page, select Manage my child's profile information.

3. On the Manage Permissions page for the account you want to change, on the right, select Edit Personal Information, then follow the instructions.

I hope these information helps somehow. Feel free to let us know if you have further questions or concerns and we will try with our knowledge to offer assistance.

Hugs!