The aws efs describe-file-systems command can be used to list the Elastic File Systems (EFS) that have been created.

~]# aws efs describe-file-systems
{
    "FileSystems": [
        {
            "OwnerId": "123456789012",
            "CreationToken": "my-efs",
            "FileSystemId": "fs-0d1500aa4f4b50839",
            "FileSystemArn": "arn:aws:elasticfilesystem:us-east-1:123456789012:file-system/fs-0d1500aa4f4b50839",
            "CreationTime": "2023-09-27T04:55:23+00:00",
            "LifeCycleState": "available",
            "Name": "my-efs",
            "NumberOfMountTargets": 1,
            "SizeInBytes": {
                "Value": 24576,
                "Timestamp": "2023-10-02T10:13:00+00:00",
                "ValueInIA": 0,
                "ValueInStandard": 24576
            },
            "PerformanceMode": "generalPurpose",
            "Encrypted": true,
            "KmsKeyId": "arn:aws:kms:us-east-1:123456789012:key/f0c9f7f5-1956-4b8d-bb2f-e0f9aa951309",
            "ThroughputMode": "bursting",
            "Tags": [
                {
                    "Key": "Name",
                    "Value": "my-efs"
                },
                {
                    "Key": "Role",
                    "Value": "AWS EFS File Storage"
                }
            ]
        }
    ]
}

Then the aws efs describe-mount-targets can be used to list the Elastic File System (EFS) Mount Targets.

~]# aws efs describe-mount-targets --file-system-id fs-0d1500aa4f4b50839
{
    "MountTargets": [
        {
            "OwnerId": "123456789012",
            "MountTargetId": "fsmt-0481f8dfc2b5c6488",
            "FileSystemId": "fs-0d1500aa4f4b50839",
            "SubnetId": "subnet-0316e4d9fcd4efccc",
            "LifeCycleState": "available",
            "IpAddress": "172.31.81.6",
            "NetworkInterfaceId": "eni-02b54b783c735dcba",
            "AvailabilityZoneId": "use1-az2",
            "AvailabilityZoneName": "us-east-1b",
            "VpcId": "vpc-014d2fcfa335d3c01"
        }
    ]
}