Hi @Hein Wai Htet ,
The Azure Subscription free account, free services are available in all countries where Azure is commercially available. Currently, it is not available in Myanmar. For details, please refer to the second half of this page - Azure free account FAQ
I am sorry for the inconvenience. We have been receiving feedback and suggestions to make unavailable regions available considering the expansion of our customers. This has already been taken up with our engineering team but there is no ETA for this to be available in the near future and there is no workaround for now.