Allow download of pdf files, with form connected to database

On my website, I currently have a form that allows me to download a dynamically generated file with data from the wordpress database, but when testing on the android device, this pdf file is not generated or downloaded. Is any additional module required to enable this app file download option?

I would suggest you display the form page in webview. You can display any page from your website in webview on the app and make it accessible via the bottom bar. If users are able to download the pdf via your mobile site, they should be able to do it in the app webview too.