SOAP Service with Service Reference

Added in .NET 3.5
This supports services that implement WS-I Basic Profile 1.1 (plus others)
This is a wrapper over svcutil.exe and creates a client proxy

WCF Services

Windows Communication Foundation (WCF)
This is a wrapper over svcutil.exe
It creates client proxies and also web.config entries.
All communications with a WCF Service occur through endpoints.
Each endpoint contains the following information:
Address - where to find the service (represented by the EndPointAddress class). Every endpoint must have a unique address.
Binding - how the communication is performed
Contract - specifies which operations are available
These must be added using the Service Reference

link - http://dneonline.com/calculator.asmx?wsdl 

Example

Open Visual Studio 2022 as Administrator.
New Project, Windows Forms App (.NET Framework) C#
Create folder C:\temp\winforms\

Create new project,
Press Next

Project name - WebServicesProject
Location - C:\temp\winforms
Framework - .NET Framework 4.8

An entry will appear under Connected Services
SS

Synchronous

Asynchronous