To understand how you deploy Azure AD, you need to understand that Azure AD is directly connected to your Azure subscription. So, the Azure account subscription administrator is always the first service administrator for your Azure environment. There can only be one account administrator per Azure subscription. The account administrator is the only one who can manage Azure AD and subscription connections. If you lose your administrator credentials or lose access to the administrator account, you can no longer manage your subscription.
You should therefore plan who will create your subscription and which account is the account administrator. To create a subscription, the subscription administrator must have a Microsoft account formerly known as a Live ID or Microsoft account, or an Azure AD account. This can be created, for example, through Office 365 before adding Azure agreements and subscription payments, or could be an account created and synchronized...