An Azure service that offers file shares in the cloud.
The object you are seeing is a failed App Service Domain resource under Microsoft.Web/domains. It is not the registrar ownership of the domain, so deleting it will not affect the copy you purchased elsewhere or its external DNS.
First open the failed App Service Domain resource, check Locks, and remove any Delete lock. Then use Cancel purchase or Delete from Overview.
If deletion still fails while provisioningState remains InProgress and subStatus is FAILED_SETUP, try deleting the exact resource ID from Azure CLI:
az resource delete --ids <full-resource-id>
If that returns Conflict, OperationInProgress, or the resource immediately reappears, stop retrying. The Microsoft.Web resource provider has a stuck purchase/provisioning record that only Azure support can clear. Open a subscription-management or App Service support request and include the full resource ID, failed deployment name, operation/correlation ID, UTC timestamp, and the JSON state you posted. Ask specifically for backend cleanup of the failed Microsoft.Web/domains resource and confirmation that no charge completed.
You do not need to remove Entra users, applications, or DNS records; those steps apply to a different type of custom domain. You can use the externally registered domain by configuring its DNS and adding it as a custom hostname to your App Service.