Hey there, Nishanta kumar Das
“But I don’t have a card, it’s asking for a card even for the free service.”
When you sign up for an Azure subscription, you must have a credit/bank card attached to the subscription. When I signed up for the Azure Student subscription, it asked me for my payment method and details.
While the subscription may be free, you can still incur charges from that subscription. This is because, not every service on Azure is free, and will incur charges if they are being used. You also have other services you can use for free for a certain time each month/year. An example of this is a virtual machine that is included in the Azure Students subscription, it allows me to use
As you can see above, I have a limit on those resources I can use for free. After I have reached these limits, I am then charged for the service using my payment method stored on Azure. This will be the same for your subscription. There will be resources that are free but have limits before it starts charging you.
The other reason you must have a payment method on file is when the subscription ends, it will move you onto a pay as you go subscription where you can continue using the resources and paying for what you have been using.
Before it charges you, it does tell you if you will get charged and how much it is going to cost you. You can manage your spending in the Cost Management service in Azure here: https://portal.azure.com/#blade/Microsoft_Azure_GTM/ModernBillingMenuBlade
Hope this explains why you must have a payment method. If you do not have a payment method, you are unable to sign up for Azure.
Hope this helps,
Nathan