Keep the EXE as a backend process and build a thin web interface.
If you own the source code of the EXE (or it’s a simple utility), the best long-term solution is to rewrite or recompile it for the web. convert exe to web application link
An EXE file is designed to run locally on a Windows operating system with direct access to hardware. A web application runs in a browser with restricted permissions. Therefore, you cannot simply "change the file extension." You must either stream the existing application or rewrite it. Keep the EXE as a backend process and
Use Emscripten to compile your C++ code into WebAssembly. convert exe to web application link