Create Records in CRM using a standalone web application?

Hi All,

         I need to create case records on CRM from a webapplication. I have already one web application in asp.net which is used by the users., My requirement is like i will add a form in that existing web application which will take the request data from users. Once they submit the form i have to create a new case record in my CRM 2016(onpremise). How to do this. Please share an example if you have.

Thanks