1. Run Microsoft Azure Active Directory Module for Windows PowerShell as administrator.
2. Connect to O365 by using the following scripts.

Install-Module -Name AzureAD

Connect-MsolService

#Log-in using your global administrator account (Other roles can also be used).

(Get-MsolUser -UserPrincipalName username@domain.com).Licenses.ServiceStatus

# This will return a list of SKUs that are enabled to the user’s account

 

If you are thinking of familiarizing all SKUs in Office 365 licenses, check this document:

https://blogs.technet.microsoft.com/treycarlee/2014/12/09/powershell-licensing-skus-in-office-365/

 

Reference: https://docs.microsoft.com/en-us/office365/enterprise/powershell/view-account-license-and-service-details-with-office-365-powershell