CertAddEncodedCertificateToStore

[DllImport("Crypt32.dll", SetLastError = true)]
public static extern IntPtr CertAddEncodedCertificateToStore(
   IntPtr hCertStore,
   uint dwCertEncodingType,
   byte[] pbCertEncoded,
   uint cbCertEncoded,
   uint dwAddDisposition,
   IntPtr ppCertContext
);

Microsoft documentation: Link