Explanation/Reference:
Explanation
B. The Install-AdcsCertificationAuthority cmdlet performs installation and configuration of the AD CS CA role service. It can be used to install a root CA.
Example:
Install-AdcsCertificationAuthority -CAType StandaloneRootCA -CACommonName "ContosoRootCA" - KeyLength 2048 -HashAlgorithm SHA1-CryptoProviderName "RSA#Microsoft Software Key Storage Provider" E: The Install-AdcsWebEnrollment cmdlet performs initial installation and configuration of the Certification Authority Web Enrollment role service.
Note: Prior to the availability of Certificate Enrollment Web Services, AD CS required that client computers configured for certificate auto-enrollment be connected directly to the corporate network. Certificate Enrollment Web Services allows organizations to enable AD CS using a perimeter network. This allows users and computers outside the corporate network to enroll for certificates.

Certificate Enrollment web service
Reference: Deploying AD CS Using Windows PowerShell