There are four different Microsoft 365 business plans as of today. Microsoft says that it changed the name to "to be more reflective of the range of features and benefits in the subscription.
(All enterprise plans require an annual commitment ... Microsoft also recently released Microsoft 365 Copilot, which Microsoft 365 business and enterprise subscribers can add for an additional ...
For most Outlook.com users, the default mailbox size is 15 GB, while Microsoft 365 subscribers enjoy a larger limit, ranging from 50 GB to 100 GB (Exchange Online) depending on the plan.