You can check the domain is available or not with any domain extension like ".com, .pk, .edu, .gov, .net and .org etc." for globally or country wise, also you can check the "Alexa" ranking by the help of search below.
If you are willing to purchase a domain then here are some good hosting prviders where you can purchase a domain which are given below.
Godaddy.com
Name.com
Namecheap.com
Register.com
