This is Microsoft Office 365 E3 Account (NOT a key) which will activate up to 5 devices on all supported platforms including Windows, macOS, Android, iOS, Tablets. You can install and activate as many times as you want on any 5 devices in 1-year period. Activation is permanent and lifetime. After subscription expiration you don’t need to buy new one to continue product usage. You can’t change the sign in email because this is E3 account.
Install the latest versions of Office client apps (Word, Excel, PowerPoint, Outlook, Microsoft Teams, OneNote, Publisher (PC only), and Access (PC only)) on up to 5 PCs/Macs, 5 tablets, and 5 mobile devices.