I can not buy bitcoins where I can buy domains anytime
I tried to buy and opened many accounts and sent documents but nothing is working for me.
Bitcoin is actually pretty easy to acquire.
First off, there are established sites like coinbase, wesellcrypto and glidera which allow for the purchase of bitcoin. Then, there are many forums where you could do a User to User exchange, but usually there is a fee. Then, you can always acquire a domain for example, and sell it for bitcoin. Mining is also an option for users with a large stock of GPUs, CPUs, Machines, etc.
You can also grow bitcoin more easily, investing and gambling are two of the options (I don't condone gambling). Then, bitcoin also extends to many more cryptocurrencies, and altcoins could also make you quite a bit of cash, if you use your time and resources to the fullest extent.
Finally, you could always "cheat" a way to buy bitcoin. Some altcoins allow an option to purchase with paypal (ex. potcoin), then you could go to any trading site (bittrex, poloniex, kraken, etc.), deposit the altcoin and then sell for bitcoin and you got yourself some bitcoin cash.
A quick guide to earn bitcoin.