Hi @araymoises, in general, you can upload any file type you want to OJS, as it does not open the files itself, but the OJS server delivers them to the client computer for opening and display. There are, however, a few exemptions to that:
The server’s admin can restrict the file formats which the server accepts as a security measure. Generally, executables, documents with macros and scripts need to be handled with great care, to prevent authors injecting malicious code to your website.
If you would like to provide full-text search capability for your OJS users, you need a tool that extracts all text from the file type for creating the search index. There are tools available for basic formats like PDF, but for other formats, this could be a challenge.
If you plan to use XML files for articles, it would be necessary to use a stylesheet or a script of some sort, so that the user sees a rendered version of your XML data.
OJS will mostly rely on the client computer’s software to display data, so that the PDF viewer plugin of the browser or the HTML displaying capabilities of the browser are used, if you don’t specify another viewer through a plugin.