You will finde all the necessary information on the Web site of the ARRL so please have a look in the "Licensing, Education & Traning" section.
Special the subsection "Getting Licensed" will be interesting for you:
Notice the validation of the question pools:
- Technician (Element 2) until 30th Juni 2022
- General (Element 3) until 30th Juni 2023
- Amateur Extra (Element 4) until 30th Juni 2020
For your exam preparation there two printed books or ebooks (Kindle) available from the ARRL for each license class:
- License Manual 4rd Edition (Technician) | Tech Q&A 7th Edition
- General Class License Manual 9th Edition | General Q&A 6th Edition
- Extra Class License Manual 11th Edition | Extra Q&A 4rd Edition
There are different possibilities of traning for your exams:
online training at the ARRL: http://arrlexamreview.appspot.com/
a nice training Web site is HamStudy.org: https://hamstudy.org/
Apps for iOS and Android mobile devices are also available like "FCC Ham Radio Test Prep" from Dauntless Software:
For iOS the apps "Amateur Radio Exam Prep" von Patrick J Maloney LLC. are usefull:
Check if the app using the latest question pool.