All except EA customers can grant access to Azure billing information by assigning one of the following user roles to members of your team:
Account Administrator
Service Administrator
Co-administrator
Owner
Contributor
Reader
Billing Reader
Reference: https://learn.microsoft.com/en-us/azure/billing/billing-manage-access
Note: You may have access to billing but not to the subscription. OR You don't have access to any subscription in the directory you've selected. So, switch to the right directory with a proper subscription you've access to.
For Cost Management: If you're an EA user, you need combination of permissions granted in the Azure portal and in the EA portal. These permissions are again defined basis scopes. For more details see this link - https://learn.microsoft.com/en-us/azure/cost-management/assign-access-acm-data