The majority of websites to watch movies online for free are illegal. There are some legal sites that provide free movie streaming, but they usually provide older or low-budget indie productions.
If you decide to use illegal sites, I suggest at least using the VPN service for your own safety.
Yes, many of them are.
But if you try Iflix as I've tried it, there are movies and series' that you can watch there for free legally. But majority of the films there are from Asia.
There are anime's too.