When you try to open a website Your computer sends some datas to webserver and then in return the web server sends you the website and you can view it. But the problem here is the webservers and even some smart hackers can trace you and they can find who are you and also can steal some important datas from your computer in this process. You can solve this problem by using proxy servers. So what proxy server is? It is a computer or computer software which will act as an intermediate when you share information on internet when you use proxy servers first you send the informations to the proxy server. And then the proxy server will get the datas from webservers and and then it will send the datas back to you. In this way if you use a proxy server the web server or hackers cant trace you and they will also not see your real ip address instead they will see the ip adress of the proxy server and think that as you. in this way you can change your identity in internet using proxy servers. the following picture will make you clear about the concept of proxy servers. But even if you use proxy servers you should never use your secret things from proxy servers like you should not log in to your bank account using proxy servers as every datas you get and send are through the proxy servers your informations might be leaked or saved by proxy server administrator or hackers. So you should use the proxy servers only to hide your identity.