When you sign up for an Azure free account, you're given $200 in credits that are valid for the first 30 days. Once the 30-day period ends, any remaining credits will expire unless you upgrade to a Pay-As-You-Go. So, No your credit will not transfer as it has correctly expired.
The 12 month period refers to some specific services that have free usage limits. These services will be billed at standard rates if you exceed the free limits.
For list of these see: https://azure.microsoft.com/en-us/pricing/free-services
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Regards,
Abiola