Microsoft 365 Business Basic Includes the Following:
Email with 50 GB mailbox.

Create a hub for teamwork to connect people using Microsoft Teams
Store and share files with 1 TB of OneDrive cloud storage per user
Office apps for the web, including Outlook, Word, Excel, PowerPoint, and OneNote (plus Access and Publisher for PC only)

Microsoft 365 Business Standard Includes the Following:
Email with 50 GB mailbox.

Create a hub for teamwork to connect people using Microsoft Teams
Store and share files with 1 TB of OneDrive cloud storage per user
Office apps for PC including Outlook, Word, Excel, PowerPoint, Access, Publisher and OneNote.

Microsoft 365 Business Premium Includes the Following:
Email with 50 GB mailbox.
Create a hub for teamwork to connect people using Microsoft Teams
Store and share files with 1 TB of OneDrive cloud storage per user
Office apps for PC including Outlook, Word, Excel, PowerPoint, Access, Publisher and OneNote

If you are purchase Perpetual Licenses, you can use the software with same version lifetime. In case you require upgrade to the next version you need to buy the upgrade separately after the release of the new version.

Subscription based license will expire as per the subscription period. Subscription period could be monthly, Quarterly or Annual.

If you purchase Software Maintenance, you will get the next version of the software free cost if the next version is released within the period of Maintenance.