Ok, regarding the change of school or GI Bill program, in what ways can I send the application? And besides doing it online, can I send what is required by mail?
Yes you must download VA Form 22 - 1995 for Veterans and service members PDF and VA Form 22 - 5495 for dependents PDF.
What if I stopped going to school but have returned recently?
Yes you must inform GI Bill of this information.