The GRE is administered around the world by GRE test centers that are recognized by the ETS. The list of available test centers (See below) is continually updated, and contains the test centers that currently offer the GRE test. Computer-based testing for the GRE is available most often at Prometric™ Testing Centers, and certain colleges and universities. In either case, the testing environment is very similar at all locations, regardless of whether you take the GRE test at a university, a private company such as Prometric, or elsewhere. In all cases, you'll be asked to show you identification and registration slip, and, you'll be supervised while taking the test.
It is crucial that you look for a test center that, ideally, is close to your home. And, when you do find that test center, be sure to sign up as soon as possible for your desired test date and time. This is very important, because test centers tend to fill up quickly, especially towards the end of the year when applications to graduate schools, and hence a need to take the GRE test, are due. Practically speaking, if your test center is far away, and you have to travel several hours to get there, then there is a greater chance that you'll be tired when you take the test or that you'll be delayed, than if you take the GRE test at a center that is close to your home.
For the computer-based general test, ETS provides a list of computer-based general test centers that you can access online. For the paper-based general test centers, find your test center in either of China, Hong Kong, Korea or Taiwan, or locate your test center at the ETS website at Test
Center locations PDF.