Official intelligence tests can be administered by third-party services or local schools and colleges. Just make sure that before you take the test at one of these places, that you do your due diligence and find out if they are certified by your high IQ society. Unless you are taking the test for your own personal knowledge, it would be a shame to spend all that time and effort in taking an in-depth intelligence test just to find out that it was not recognized due to lack of certification for your testing facility. Contact your local high intelligence society, or chapter, to make sure the test and facility are recognized by them and allowed to be used as methods for official membership.
Most official intelligence tests will have to be administered by a licensed psychologist to make sure the test is accepted as valid and uncompromised. Such tests usually have a minimal cost associated with them, to account for the proctor's time, as well as the materials needed to print the test. That said, the environment created by the testing atmosphere on an official test can be quite different from that of a practice environment, which is why it is important to take as much time as needed to properly prepare for the challenge of an official intelligence test. Making sure you are completely acquainted with the style and presentation of the questions on an intelligence test will help you stay focused and on track during the official test. A practice environment that allows you the most flexible use of your time to study will help you prepare for the official test by allowing you to anticipate the style and composition of questions on the official intelligence test. Also, a practice environment developed to work optimally on both desktop and mobile means that you can take your studies on the road and grow you abilities even as you commute.