A have never done any web application, so please excuse me if my question is stupid,
is there a simple way to convert a Lazarus desktop application into a web application?
None that I know.
Take a look on these videos to have an idea of what a web application might be:
HTML 5, CSS 3, PHP , Jquery, Ajax website design (E.commerce) - Younes RM
https://www.youtube.com/playlist?list=PLQsP7Ksoaqq1JZQqd3K2O5a5ic9R5TUQqThere are many languages, frameworks and technologies you could choose from, including Pascal CGIs:
CGI (Common Gateway Interface).
https://en.wikipedia.org/wiki/Common_Gateway_InterfaceObject Pascal para Web - aula 00 - Zendrael
https://www.youtube.com/watch?v=wRRDjQk9kjMFormulario de cadastro simples para web com Lazarus e fcl-Web - ANDERSON JUNIOR GADO DA SILVA
https://www.youtube.com/watch?v=iZNx-44Rtn8I have been consulting for teams that develop only desktop, desktop + web, desktop + mobile, desktop + web + mobile. And teams that decided to migrate from desktop to web, to mobile, and to web + mobile.
It's not easy at all. It demands a lot of hard work keeping everything fast, UX and UI high quality, integrated and making sense.