Global and Local

# global
$foo = "abc"

function fun {
  $foo = "dfg"
  
  # output: abc
  Write-Host $global:foo
  
  # output: dfg
  Write-Host $local:foo

  # output local variable: dfg
  Write-Host $foo
}

# call function
fun

# output abc
Write-Host $local:foo

# output abc
Write-Host $foo