This is answered under ASP.NET Web Service template not exist?, but to reiterate
Make sure that you set the Framework to .NET Framework 3.5 or you won’t find the Asp.Net Empty Web application.
Go to File –> New –>Asp.Net Empty Web application. On that Application Right click –> Add –> New item – > Web Service (ASMX).
OR
Right click on your Solution –> Add –> New Project –> confirm you are set on .NET framework 3.5 –> Visual C# or Visual Basic –>Asp.Net Empty Web application. Name project. On that project Right click –> Add –> New item – > Web Service (ASMX).
For the naysayers. Answer the question. Don’t berate the Poster. If you have a better idea then tell the Poster how or link the Poster to the a tutorial. Stop displacing your anger on others.
I am stuck in the same bind. Customer wants to dump a post to an ASMX. I talked to them, but this is how they have always done it and they won’t change. Sometimes ya gotta do what ya gotta do. Just rub the zombie gore on yourself and wander through the zombie horde. BRAINSSSS