Microsoft 365 gives a company email (Exchange Online), Office apps, file storage (OneDrive, SharePoint) and Teams under one account. Everything runs in the cloud and works from a computer or a phone.
Correct setup matters: MFA on every account, separate admin accounts, and removing access when someone leaves. Also keep in mind that storing data in the cloud doesn’t automatically mean a full backup.
Example
A new employee gets email, Teams and access to shared folders on day one — all from a single account.