What is provillage access in computer langauge?

Hi member.Please tell me with full details about provillage access in networking langauge?for example if i want to change any Ip address in of any computer so when i click on properties of a netwok system then a message will show on the screen that is your don't have provillage access so what is that please tell me fulll brief and also tell me how can i access and get fulll command on the computer?