The version contains all Office programs Word, Excel, Powerpoint, OneNote, Outlook. You also get 1 terabyte of online storage on OneDrive. In total, you can install the version on a PC or Mac, a tablet or iPad and 1 mobile phone, but the version is limited to 1 user.
Office 365 is the subscription version of Office, so you buy an annual license that you need to renew after expiration. If you already have an Office 365 subscription, you can also extend it.
You purchase the software from Amazon as a download and then receive an activation code via email.