Hello yzr,
Thanks for your question.
The models of AWS and Azure are different per free trial.
Azure provides access to certain free-tier services for 12 months, but only if you upgrade to a pay-as-you-go subscription after the free credit expires.
Your subscription and services are disabled when your credit runs out or expires at the end of 30 days.
After you upgrade, you'll have continued access to free services for 12 months and you get charged only for usage beyond the free services and quantities.
The above is documentated here: https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/avoid-charges-free-account?source=recommendations
Please let me know if you need more clarification from me.
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola