what is the required age for an apple id?

Here are the official terms:

This iTunes Service is available for individuals aged 13 years or older. If you are 13 or older but under the age of 18, you should review this Agreement with your parent or guardian to make sure that you and your parent or guardian understand it.

For a child under 13, it would appear that the parent should open and manage the account on behalf o the child.

Regards.

Welcome to the Apple community.

I believe the minimum age requirement is 13, however I also believe that minors can use an Apple ID, provided it is set up by a parent or legal guardian.