Sharepoint in O365 is a cloud based service, instead of installing sharepoint server at on-prem, businesses can subscribe O365 and access sharepoint online service.
Organizations use sharepoint to create websites.
Employees can create sites to share documents and information from any device.
You need a browser to access this service.
Create a site:
Go to Microsoft 365 admin center / users / active users/ select user and click Licenses and app tab and check the licesne assigned to user and in the bottom it gives total apps assigned to user.
To access sharepoint: in browser type office.com using work or school account and in the upper left corner select app launcher (9 dots square) and click sharepoint.