$TokenSet = @{
    U = [Char[]]'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    L = [Char[]]'abcdefghijklmnopqrstuvwxyz'
    N = [Char[]]'0123456789'
    S = [Char[]]'!"#$%&''()*+,-./:;<=>?@[\]^_`{|}~'
}
    
$Upper = Get-Random -Count 5 -InputObject $TokenSet.U
$Lower = Get-Random -Count 5 -InputObject $TokenSet.L
$Number = Get-Random -Count 5 -InputObject $TokenSet.N
$Special = Get-Random -Count 5 -InputObject $TokenSet.S

$StringSet = $Upper + $Lower + $Number + $Special

$RdString = (Get-Random -Count 15 -InputObject $StringSet) -join ''

#You can use now $RdString in your script to make a random password to an AD user or other stuff...