I have a 400 page book on printer programming. Not all commands work for all breeds of printers. That can be a problem, especially if it hit default settings. And yes, you can change the printer's defaults so when you shut it off and restart it, the defaults don't return to your previous settings.
Spammers are embedding malicious code in container, archive, or compressed media files that supposedly contain something you want to open or install. PDFs, MSI, etc. If you receive emails that have container files attached, be very careful. Make sure they are from a reliable source.
There are other safer and more reliable ways of transferring large files.