We are all here pure volunteers. We do not have time or motivation to do Google queries for you.
In case you do not know how you can search the web for any infos you might need you maybe want to read this article[^].
Neither we are machines or heartless geeks. Anyone understands when your first question is not too good and some info went missing while asking. But for the future: Consider these guidelines[^] when asking a question.
And the most important thing: Be polite and use punctation marks.
Nutshell: ASP.NET does NOT have any inbuilt API support to send out an SMS. You need to go for a third party solution or use something that is found on the Internet. Articles and discussions above should help you out.