Carlos upgraded his Samsung Galaxy S5 from Sprint to the Galaxy Note 4 with Verizon. But it comes with a lot of stuff he doesn't like. Leo says that Carlos can root it, but that requires unlocking the boot loader which involves a risk of bricking the phone. Carriers don't like it because it's a workaround for how they want him to use the phone, like tethering at no cost.
If he wants to learn how to root the phone, then he can head over to XDA-Developers Forums. He can also pay a bit more and get an international phone that comes unlocked.
Carlos would also like to have access to his email and documents on any device. Leo says that using an IMAP server like GMail will handle email on every device because it keeps all the mail on the server.