@Anupam Nath We are sorry to hear you are encountering this issue. It sounds like a UI/UX issue that you are encountering.
Are you using the standard portal? (https://portal.azure.com)?
If so, can you please try creating the resource via the preview portal to see if this helps to resolve the issue? (https://preview.portal.azure.com).
I can see the storage account option in either portal but I hope the preview portal might assist you.
The only other item I can think of is to ensure you have selected a resource group within the basics tab.
Please let us know if you are still encountering this issue. We look forward to your reply.