If you are creating certificate requests to enroll certificates programmatically and using a code like the following: How to create a certificate request with CertEnroll and .NET (C#), you may need to export the enrolled certificate after you get the response from the Certificate Authority.
You may export the certificate and its private key to a .PFX file by using this mehod:
Or if you don't need the private key and you would like to get a .CER file instead, you may use this property:
You may get that property as Base64 or Binary string (by using the appropriate EncodingType enumerator), and write it to a file with .CER extension.
Alex (Alejandro Campos Magencio)