1.1.1.1: Fast, privacy-first consumer DNS service

Three novice questions, please:

1) A VPN gives you privacy but this prevents your ISP from even knowing you're using a VPN, correct?

2) This is a change you make to your wifi router, correct?

3) What is you're not on wifi, or you're using public wifi, is it possible to still benefit from this?

Thanks in advance. I'll wait for my answers off the air :)

1) These requests are all in the clear, so your isp can read them and see which hosts you're asking for. VPNs provide better privacy (assuming you choose a private one).

2) yup

3) often. You can set it on your computer, but some public WiFi systems will block it.