This means that you should not be using the PowerShell cmdlets that include "msol" in their name (following the "-" character).
Instead, you should be using cmdlets which include "mg" in their name (following the "-" character).
To create a user, follow https://learn.microsoft.com/en-us/microsoft-365/enterprise/create-user-accounts-with-microsoft-365-powershell?view=o365-worldwide
To set a license, follow https://learn.microsoft.com/en-us/microsoft-365/enterprise/assign-licenses-to-user-accounts-with-microsoft-365-powershell?view=o365-worldwide
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hth
Marcin