By default, when you want to block or allow some IP(s) from your website, you may simply do it as the following rules from .htaccess,
order deny,allow deny from all allow from 18.104.22.168 allow from 22.214.171.124
However, if you are using service like CloudFlare or other CDN service, you can not do like this as Apache do not understand your visitor IP.
To do that, you need to do like rules below,
SetEnvIf X-FORWARDED-FOR 126.96.36.199 allow SetEnvIf X-FORWARDED-FOR 188.8.131.52 allow order deny,allow deny from all allow from env=allow
If you need it for IP ranges or network block such as 184.108.40.206/24, you may do it like,
SetEnvIf X-FORWARDED-FOR "^1\.1\.1\.*" allow order deny,allow deny from all allow from env=allow