I understand that you are trying to customize user attributes during sign-up in Microsoft external tenants.
Based on the information provided, it seems you are trying to change the label names of built-in user attributes, but they are not reflecting during the sign-up flow. This is expected behavior because you are modifying default attributes.
To customize labels on page layouts, first create custom attributes at the tenant level so they can be used in any user flow within the tenant. Then, assign the attribute to your sign-up user flow and configure how you want it to appear on the sign-up page.
Follow below steps:
1.Create custom attributes > Microsoft Entra ID > External Identities > Custom user attributes.
2.Include the custom user attribute in a sign-up flow during creation.
For your reference: https://learn.microsoft.com/en-us/entra/external-id/customers/how-to-define-custom-attributes
Hope this helps. Do let us know if you any further queries.
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