How to configure Azure subscription policies

Navigate to the Azure portal by opening https://portal.azure.com
In the left-hand menu, select Subscriptions (this is if you added it to your favorites; otherwise, take the steps that we described in the previous demonstration).
In the Subscriptions overview blade, in the left-hand menu under Settings, select Policies:
In the Policies overview blade, select Assign policy to create a new policy:
On the next screen, we’re going to create a definition for our policy. Add the following values to create the policy so that resources for this subscription can only be created in selected regions:
1. Scope: The subscription name.
2. Exclusions: Leave this blank; we are going to create a policy that applies to the entire subscription.
3. Policy definition: When you select this, you can choose from a number of available policies that you can apply to your subscription. Microsoft has created these JSON templates for you, based on the best practices from different enterprises. You can create your own templates here as well. Select a policy from the list (for instance, Allowed locations), and then click Select.
4. Assignment name: This is automatically filled in after selecting the policy.
  Parameters: Here, you can select the allowed locations where users can deploy their resources. For instance, select Central US
After selecting the different regions, click the Create button: