Amazon RDS for Oracle offers two licensing options: License Included (LI) and Bring Your Own License (BYOL).
In the License Included model, you do not need to purchase an Oracle license separately, as the license is included with AWS.
If you already have an Oracle license, you can apply it using the Bring Your Own License (BYOL) model. Amazon RDS supports the BYOL model only for Oracle Database Enterprise Edition (EE) and Oracle Database Standard Edition Two (SE2).
To use Multi-AZ deployments, you need twice the number of licenses required for a Single-AZ deployment to cover the standby DB instance. In this case, you should review your Oracle software license agreement and comply with Oracle licensing policies.