Most of the time, you only need to take GRE General Test. It consists of three parts: Verbal Reasoning, Quantitative Reasoning, and Analytical Writing. It costs $160 for the test. You need to register for your test. Go to GRE website for more details.
Make sure you know the average GRE scores of admitted applicants for the schools you are aiming. This will be a benchmark for you. You should try to score within the average score – however realize that GRE is only one of the considerations for admission. Don’t spend all you time getting the highest GRE score and failing in other parts.
When taking the GRE test, you can submit up to 4 institutions (schools) that you want the score to be sent to. Use this opportunity. If you do not feel the schools, you can do it later – however it will cost you $15 per score recipient.