Microsoft Office 365 enables you to work anyplace, anytime and on any device. It’s available in a number of different packages.
Exchange Online – the entry level Office 365 has a 50Gb mailbox; shared calendar and contacts, plus a 99.9% availability guarantee.
Office 365 Business Premium and Office 365 E3 are more comprehensive. They provide Exchange online, as well as the latest Office suite on up to five devices; 1TB cloud storage, online meetings via IM and HD video conferencing via Skype for Business.