Add docs.

README.md

@@ -1,10 +1,20 @@
 # encrypted-dns-configs
-Configuration profiles for [DNS over HTTPS](https://en.wikipedia.org/wiki/DNS_over_HTTPS) and [DNS over TLS](https://en.wikipedia.org/wiki/DNS_over_TLS).
+Configuration profiles for [DNS over HTTPS](https://en.wikipedia.org/wiki/DNS_over_HTTPS) and [DNS over TLS](https://en.wikipedia.org/wiki/DNS_over_TLS). 
 
 Check out the article for more info: [paulmillr.com/posts/encrypted-dns/](https://paulmillr.com/posts/encrypted-dns/)
 
 ## Installation
 
-To make settings work across all apps in iOS & MacOS, you’ll need to install configuration profile. This profile would tell operating system to use DOH / DOT. Note: it’s not enough to simply set server IPs in System Preferences — you need to install a profile.
+To make settings work across all apps in iOS 14 & MacOS Big Sur, you’ll need to install configuration profile. This profile would tell operating system to use DOH / DOT. Note: it’s not enough to simply set server IPs in System Preferences — you need to install a profile.
 
 On iOS, after installation, go to system **Settings => General => Profile**, select downloaded profile and click “Install” button.
+
+## Docs
+
+To verify resolver IPs and hostnames, compare mobileconfig files to the following documentation.
+
+- Alibaba https://www.alidns.com/faqs/#dns-safe
+- AdGuard https://adguard.com/en/adguard-dns/overview.html#instruction
+- Cloudflare https://developers.cloudflare.com/1.1.1.1/dns-over-https
+- Google https://developers.google.com/speed/public-dns/docs/secure-transports
+- OpenDNS https://support.opendns.com/hc/en-us/articles/360038086532