I want to use a network folder to store a downloaded file from this method.

<add key="ProofFileSavePath" value="D:\\Websites\xyz\ABC\Files\" />

private async Task DownloadPdf(string proofFileUrl, long batchFileDetailId, string renderedRawId, bool isNewFileForRenderedRawId, string masterProofFileDownloadDate)
{
    var methodName = "DownloadPdf";
    if (!string.IsNullOrEmpty(proofFileUrl))
    {
        if (isNewFileForRenderedRawId)
        {
            using (var client = new WebClient())
            {
                var uri = new Uri(proofFileUrl);
                client.DownloadFileCompleted += DownloadFileCallback;
                var fileInfo = new FileInfo(uri.AbsolutePath);
                if (!string.IsNullOrEmpty(fileInfo.Extension))
                {
                    var proofFileName = Path.GetFileName(uri.LocalPath);
                    client.QueryString.Add(Constants.BatchFileDetailId, batchFileDetailId.ToString());
                    client.QueryString.Add(Constants.ProofFileName, proofFileName);
                    client.QueryString.Add(Constants.RenderedRawId, renderedRawId);
                    var proofFileSaveFullPath = Path.Combine(CommonUtil.ProofFileSavePath, proofFileName);
                    await client.DownloadFileTaskAsync(uri, proofFileSaveFullPath);
                }
            }
        }
        else
        {
            UpdateIsProofReadyFlag(batchFileDetailId, proofFileUrl, renderedRawId, masterProofFileDownloadDate, false);
        }
    }
    else
    {
        _loggingHelper.Log(LoggingLevels.Error,
            "Class: " + _className + " :: " + methodName + " :: " +
            "Proof File Url not found");
    }
}

<add key="ProofFileSaveNetworkPath" value="\\ServerName\ShareName\" />
		<add key="ProofFileSaveNetworkUid" value="yourUsername" />
		<add key="ProofFileSaveNetworkpwd" value="yourPassword" /> 

private async Task DownloadPdf(string proofFileUrl, long batchFileDetailId, string renderedRawId, bool isNewFileForRenderedRawId, string masterProofFileDownloadDate)
        {
            var credentials = new NetworkCredential(CommonUtil.ProofFileSaveNetworkUid, CommonUtil.ProofFileSaveNetworkpwd);
            CredentialManager.SaveCredentials("NetworkCredentials", credentials);

            var methodName = "DownloadPdf";
            if (!string.IsNullOrEmpty(proofFileUrl))
            {
                if (isNewFileForRenderedRawId)
                {
                    var networkFolder = CommonUtil.ProofFileSaveNetworkPath;
                    
                    using (var client = new WebClient())
                    {
                        var uri = new Uri(proofFileUrl);
                        client.DownloadFileCompleted += DownloadFileCallback;
                        var fileInfo = new FileInfo(uri.AbsolutePath);
                        if (!string.IsNullOrEmpty(fileInfo.Extension))
                        {
                            var proofFileName = Path.GetFileName(uri.LocalPath);
                            client.QueryString.Add(Constants.BatchFileDetailId, batchFileDetailId.ToString());
                            client.QueryString.Add(Constants.ProofFileName, proofFileName);
                            client.QueryString.Add(Constants.RenderedRawId, renderedRawId);
                            var proofFileSaveFullPath = Path.Combine(networkFolder, proofFileName);

                            if (credentials != null)
                            {
                                client.Credentials = new NetworkCredential(credentials.UserName, credentials.Password);
                            }

                            await client.DownloadFileTaskAsync(uri, proofFileSaveFullPath);
                        }
                    }
                }
                else
                {
                    UpdateIsProofReadyFlag(batchFileDetailId, proofFileUrl, renderedRawId, masterProofFileDownloadDate, false);
                }
            }
            else
            {
                _loggingHelper.Log(LoggingLevels.Error,
                    "Class: " + _className + " :: " + methodName + " :: " +
                    "Proof File Url not found");
            }
        }