Is there any built-in mechanism to convert files to PDFs when uploading them to the media library, or does someone know of functionality that can accomplish same?
Could you please specify further what type of "files" you would like to convert to PDF? Also for which version of Sitecore?– Peter ProcházkaMay 22, 2018 at 15:01
This question lacks sufficient detail to be able to answer in a meaningful way apart from "No, there is nothing OOTB, yes you can do anything you want in Sitecore". More detail and what you have tried so far would be a good start.– jammykamMay 22, 2018 at 15:48
No, there is no built-in way to do this.
You can build a module that converts the files to PDF using iTextSharp, PhantomJS or Puppeteer.
Once upon a time @adamnaj wrote a script to export media items to PDF using Sitecore PowerShell Extensions. Maybe you can use that idea to import them back into the media library after PDF generation.