Create-CustomTaxonomyTerm.ps1

# Configuration
$SiteUrl = "https://TENANTID.sharepoint.com"
$TermGroupName = "Contoso"
$TermSetName = "Document Types"
$TermName = "Reports"
$TermLcid = 1033
$TermGuid = "2bdb40fd-02e4-4604-914e-9f8012685be0"

# Get correct termset
Connect-PnPOnline -Url $SiteUrl -Credentials $GlobalCredentialsId

$Context = Get-PnPContext

$TaxonomySession = [Microsoft.SharePoint.Client.Taxonomy.TaxonomySession]::GetTaxonomySession($Context)
$TermStores = $TaxonomySession.TermStores
$Context.Load($TaxonomySession)
$Context.Load($TermStores)
Execute-PnPQuery

$TermStore = $TermStores[0]
$Context.Load($TermStore)
Execute-PnPQuery


$Group = $TermStore.Groups.GetByName($TermGroupName)
$TermSet = $Group.TermSets.GetByName($TermSetName)
$Context.Load($Group)
$Context.Load($TermSet)
Execute-PnPQuery

# Create new term
$Term = $TermSet.CreateTerm($TermName, $TermLcid, [System.Guid]::Parse($TermGuid))
$Context.Load($Term)
Execute-PnPQuery

Disconnect-PnPOnline