Integration of WordPress with Office 365 / Azure AD can be configured in one of the following two ways:
- Shared All subsites in the network share the same Azure AD App registration and all users ‘enter’ the network through the main site and gain access to all subsites with a single login.
- Dedicated Each site in the network is treated isolated from the other and each one will have to be configured individually. It is still possible to use a single Azure AD App registration but at the very least you’ll need to add each site’s URL as Redirect URI.
For further technical details please refer to the Configuration documentation