How do you configure secure DNS (aka "private DNS") with cloudflare?

note: there are a lot of DNS questions on android.stackexchange.com I'm creating this question because all the other DNS questions were for different scenarios and I wanted to keep this up to date over the years. I do not want my DNS queries to be unencrypted whenever I am doing any internet activity (either through cellular mobile internet or through wifi with home internet). ### How do you configure secure DNS (aka "private DNS") with cloudflare?