Hi @sns ,
Based on the research, the newly created unlicensed user can access the public SharePoint site(Everyone except external users can access it directly) and can't access the private SharePoint site directly.
The unlicensed user in Office 365 can't use most of the service: OneDrive, Office online, Exchange online etc. The user needs the corresponding license to use the corresponding service.
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As the post mentioned:
With regard to the Admin account, you could set it up as a shared mailbox, and provide relevant access to people who need it (or forward the emails to an individual). If you don't intend on receiving emails to the Admin account, you probably don't need to license it at all.
As the official article mentioned, usually users have Gobal admin permissions can:
Please refer to related posts for more information:
Office 365 Unlicensed user
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