Hi @Eduardo Zunin - Grupo CIR ,
The "Access to Azure Active Directory" subscriptions are a legacy subscription type that are no longer used. They were used prior to the current Azure Portal (https://portal.azure.com). At that time the classic Azure portal only allowed access if the user had a subscription they were at least co-administrator on. This caused issues when the Azure AD admin didnt have an Azure resource subscription necessarily, so these "dummy" subscriptions were created for such access.
Today no such access is required as we now separate Azure Active Directory permissions and Azure RBAC (subscription) permissions. You can read this blog post for a bit more history if you are interested: https://techcommunity.microsoft.com/t5/Enterprise-Mobility-Security/Azure-AD-Mailbag-Azure-Subscriptions-and-Azure-AD/ba-p/249661
If you currently have active resources in your Access to Azure Active Directory subscription, please upgrade to a new pay-as-you-go subscription by submitting a support ticket below. https://ms.portal.azure.com/#view/Microsoft_Azure_Support/HelpAndSupportBlade/~/overview/newsupportrequest/
If you don't have any resources in the subscription, I can confirm for you that there is no harm that can be done by closing/ deleting this subscriptions from your tenant.
You can self-service cancel the subscription following the steps here:
Cancel and Delete your Azure Subscription
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