SharpCifs.Std is .Net Standard implements.
You can use on .NetFramework4.6 or higher, .NetCore1.0, and Xamarin.
Here is NuGet package.

Use it like this:

//reading file
var file = new SmbFile("smb://UserName:Password@ServerName/ShareName/Folder/FileName.txt"));
var readStream = file.GetInputStream();
var buffer = new byte[1024*8];
var memStream = new MemoryStream();
int size;
while ((size = readStream.Read(buffer, 0, buffer.Length)) > 0)
    memStream.Write(buffer, 0, size);
    
Console.WriteLine(Encoding.UTF8.GetString(memStream.ToArray()));

//writing file
var file = new SmbFile("smb://UserName:Password@ServerName/ShareName/Folder/NewFileName.txt"));
file.CreateNewFile();
var writeStream = file.GetOutputStream();
writeStream.Write(Encoding.UTF8.GetBytes("Hello!"));

SharpCifs.Std is .Net Standard1.3 implements.
You can use on .Net Framework4.6 or higher, .Net Core1.0, and Xamarin.iOS/Android
Here is NuGet package.

Use it like this:

//reading file
var file = new SmbFile("smb://UserName:Password@ServerName/ShareName/Folder/FileName.txt"));
var readStream = file.GetInputStream();
var buffer = new byte[1024*8];
var memStream = new MemoryStream();
int size;
while ((size = readStream.Read(buffer, 0, buffer.Length)) > 0)
    memStream.Write(buffer, 0, size);
    
Console.WriteLine(Encoding.UTF8.GetString(memStream.ToArray()));

//writing file
var file = new SmbFile("smb://UserName:Password@ServerName/ShareName/Folder/NewFileName.txt"));
file.CreateNewFile();
var writeStream = file.GetOutputStream();
writeStream.Write(Encoding.UTF8.GetBytes("Hello!"));