Hi Saqib Ahmed,
Thank you for posting your query on Microsoft Q&A. I am Saiteja from Q&A will be assisting you with your query.
Based on your query, I understand you would like to transfer the region of your Azure AD B2C to Australia region from US.
Azure AD B2C cannot be migrated as one to a different zone and currently we do not availability in Australia. I believe your B2C is available now in West US1 or WestUS2. Here is the Microsoft document which confirms the available zones for B2C and other services as well: https://azure.microsoft.com/en-us/explore/global-infrastructure/products-by-region/table
If you would like to migrate users to different directory you can follow this migration document: https://github.com/azure-ad-b2c/user-migration/blob/master/seamless-account-migration/README.md.
I hope this information is helpful. Please feel free to reach out if you have any further questions.
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