SFTP/FTP Operations from C# (.net framework 4.6.2)

Use the SSH.NET NuGet package. This can do everything you need.
var client = new SftpClient("<ip/dns>", 22, username, password); // You can aslo use a private key file
client.UploadFile(stream, "/documents/document1.docx");
client.DownloadFile("/documents/document2.docx", stream);
client.Delete("/documents/document1.docx");
client.Disconnect();
client.Dispose();

@mitesh patel , Based on my search, I find some useful links I have done related to your question.

Upload file: How to upload files with .db format from a remote server to a local server?

Download file: Unable to delete files from a remote directory with SFTP?

Delete file:Unable to delete files from a remote directory with SFTP?

For their differences, please install nuget package SSH.NET if you want to do some oprations in SFTP.

Please use the System.Net in your app if you want to use FTP.

Hope my explanation could be helpful for you.

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FTP requests go through the same types as HTTP via the FtpWebRequest type. This is a low level wrapper around the FTP calls. A full example is provided in the link provided. This type is built into the framework and therefore you don't need anything else.

However many people find the library to be limiting as it is really low level and based upon WebRequest which tries to normalize all network calls. As such it can be difficult to work with. Many people switch to a more powerful FTP library that can be downloaded from Nuget. FluentFtp is very popular but I have no experience with it. I find this site to be useful for figuring out the most popular Nuget packages but you still should evaluate each one for your specific requirements.

There is WinSCP