If my browser (Firefox) knows what the file type is, then it opens it so that I can read it. That works with MS Office stuff, PDFs, JPGs and a few more.
Avast spots the infected ones, and they don't get downloaded at all (that's worked for years).
If it doesn't know what it is, then it puts it into the Downloads folder. I don't let the machine fill up my boot drive with downloaded tat - Firefox knows to put everything into I: \Downloads, which is reserved for that.
It displays files by "date of arrival" so the most recent is always at the top of the list. Keeps it simple for simple little me.