Setting a Principal in an access policy will effectively grant users, accounts, or services with access to each SNS Topic. For more information on how to properly assign a Principal within the SNS policy, see the AWS documentation.
References:
https://docs.aws.amazon.com/sns/latest/dg/sns-access-policy-use-cases.html
In AWS Console -
In Terraform -
References:
https://docs.aws.amazon.com/sns/latest/dg/sns-access-policy-use-cases.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sns_topic