Auto generate files.

Your server might be hacked/compromised.
One thing you could try is to change your login credentials for your Web Hosting/Server and/or FTP.
If that doesn't fix it, I'd recommend contacting the owner of your Web Hosting/Server.

Tip: Try to keep your WordPress version up-to-date. There's new vulnerabilities getting released almost every week or so.

I wouldn't recommend using WordPress at all, but if you are a beginner, it's fine.