Will my ISP know that I’m using TOR if i change me DNS servers to cloudfare??
Two answers for you in the links below.
The provider is (usually) only involved in forwarding the data between client (your browser) and server, but not in requesting the data from the server itself. The main difference between using the DNS from your ISP vs using a different DNS server is that another DNS server now resolves the query for you. This might be desired if one does not trust the ISP and fears blocking of sites or logging of what sites you access (i.e. privacy invasion). It might also be desired if the new DNS provider offers some useful features, like blocking malicious domains.