Use PowerShell to assign the 'Power BI Free' license to all users in the tenant. This makes sure they will not get the 'welcome wizard' to setup their account for the first time.

Assign AD Users Power BI Free license.ps1

# install module
Install-Module AzureAD -Scope CurrentUser # if already installed you can skip this line
Import-Module AzureAD # if already imported you can skip this line

# connect
Connect-AzureAD # this will initiate a dialog to enter credentials

# Find the SkuID of the license we want to add - in this case the Power BI Free license, which is called "POWER_BI_STANDARD"
$PowerBIFreeSKUId = Get-AzureADSubscribedSku | Where-Object {$_.SkuPartNumber -eq "POWER_BI_STANDARD"} | Select -ExpandProperty SkuId

# Check how many license units are available
$ConsumedPowerBIFreeLicenses = (Get-AzureADSubscribedSku | Where-Object {$_.SkuPartNumber -eq "POWER_BI_STANDARD"}).ConsumedUnits
$EnabledPowerBIFreeLicenses = (Get-AzureADSubscribedSku | Where-Object {$_.SkuPartNumber -eq "POWER_BI_STANDARD"} | Select -ExpandProperty PrepaidUnits).Enabled

# Get all AD Users Accounts without a Power BI Free License
$UsersWithoutPowerBIFree = Get-AzureADUser -All $true | Where-Object {($_.AssignedLicenses).SkuId -ne $PowerBIFreeSKUId -and $_.AccountEnabled -eq $true -and $_.UsageLocation -ne "" -and $_.UsageLocation -ne $null}
$UsersWithoutPowerBIFree.Count #show count of users without free license

# Check if there are enough licenses to cover the users without license, and stop if not the case
if ( $UsersWithoutPowerBIFree.Count -gt ($EnabledPowerBIFreeLicenses-$ConsumedPowerBIFreeLicenses)){
    throw "Not enough licenses! There are $EnabledPowerBIFreeLicenses licenses in total, $ConsumedPowerBIFreeLicenses already consumed.. not enough for $($UsersWithoutPowerBIFree.Count) users!"
}

# Create the objects we'll need
$Assignedlicense = New-Object -TypeName Microsoft.Open.AzureAD.Model.AssignedLicense
$Assignedlicenses = New-Object -TypeName Microsoft.Open.AzureAD.Model.AssignedLicenses

# Set the SkuId correctly
$Assignedlicense.SkuId = $PowerBIFreeSKUId

# Set the Power BI license as the license we want to add in the $licenses object
$Assignedlicenses.AddLicenses = $Assignedlicense

####
# THIS IS WHERE IT ALL HAPPENS :)
#
# For all the AD users without a license, call the Set-AzureADUserLicense cmdlet to set the license
$UsersWithoutPowerBIFree | Set-AzureADUserLicense -AssignedLicenses $Assignedlicenses
#
####

# Doublecheck: Get all AD Users Accounts without a Power BI Free License again
$UsersWithoutPowerBIFree = Get-AzureADUser -All $true | Where-Object {($_.AssignedLicenses).SkuId -ne $PowerBIFreeSKUId}
$UsersWithoutPowerBIFree.Count #show count of users without free license

Can anyone suggest how and where to modify this to assign licenses to specific O365 accounts?? I should create an array containing user IDs and cycle through that?? Thank you, Tom