Generate new random password with PowerShell

New-RandomPassword.ps1

function New-RandomPassword
{
    param(
        [Parameter(Mandatory=$false)]
        [int]$Length=8
    )

    begin {

    }

    process {
        $numericChars=@(
            '0123456789'.ToCharArray()
        )
        $upperCaseChars=@(
            'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.ToCharArray()
        )
        $lowerCaseChars=@(
            'abcdefghijklmnopqrstuvwxyz'.ToCharArray()
        )
        $specialChars=@(
            "{|}/>(<&*,!@;+#[]\~.):?%$'`"".ToCharArray()
        )
        $allChars=@(
            $numericChars
            $upperCaseChars
            $lowerCaseChars
            $specialChars
        )
        
        # Make sure one character of each group will exist in the password
        $randomChars=@(
            $numericChars | Get-Random
            $upperCaseChars | Get-Random
            $lowerCaseChars | Get-Random
            $specialChars | Get-Random
        )
        # Add random character from all groups 
        $randomChars+=$allChars | Get-Random -Count ($Length - $randomChars.Length)

        # Randomize and stringify
        (-join ($randomChars | Get-Random -Count $randomChars.Length)).ToString()
        
    }

    end {

    }
}

Example 1

PS C:\> New-RandomPassword
NHOZ1&k>

Example 2

PS C:\> New-RandomPassword -MinumumLength 16
yEeqWT),MK0&|x{<