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 2026
- General (Element 3) until 30th Juni 2027
- Amateur Extra (Element 4) until 30th Juni 2024
You will find more information about the question pools on the Web site of the NCVEC.
For your exam preparation there two printed books or ebooks (Kindle) available from the ARRL for each license class:
- License Manual 5rd Edition (Technician) | Tech Q&A 8th Edition
- General Class License Manual 10th Edition | General Q&A 7th Edition
- Extra Class License Manual 12th Edition | Extra Q&A 5rd Edition
There are different possibilities of traning for your exams:
Online training at the ARRL: http://arrlexamreview.appspot.com/
If you are using other apps check if they are using the latest question pool.