Hi @trung nguyen,
To try Azure Databricks, you need to have a “Pay-As-You-Go” subscription.
Azure Free Trail has a limit of 4 cores, and you cannot create an Azure Databricks cluster using a Free Trial Subscription because creating a spark cluster requires more than four cores.
If you have a free account, go to your profile and change your subscription to pay-as-you-go.
Then, remove the spending limit, and request a quota increase for vCPUs in your region.
When you create your Azure Databricks workspace, you can select the Trial (Premium - 14-Days Free DBUs) pricing tier to give the workspace access to free Premium Azure Databricks DBUs for 14 days.
Refer "Sign up for a Free Azure Databricks Trial" for more details.