Insert Statements From Xamarin Button Press to ASP.NET API TO SQL Server

Greetings - I have a Asp.Net API set-up that will query my SQL Server and return XML data for select statements. I now need to take this a step further and from within my app allow a user to register which would then create the need for insert statements. From a button press event in my Xamarin App - how can I take the data from 6 fields on a [login to view URL] and send them to my Asp.net API and insert them into my SQL Server database?