Store creds in a secure manner

CredStore.ps1

function Get-ConfigData {
    Param(
        $Path = "$env:TEMP\MyScriptDefaultCredStore.config.clixml"
    )
    if (Test-Path -Path $Path) {
        # Open Config file if exists
        $ConfigData = Import-Clixml $Path
    }
    else {
        # Create Config file if does not exists
        $ConfigData = @{
            LastUpdateDate = (Get-Date).ToUniversalTime().AddHours(-5) # -5 for CST
            Credential     = (Get-Credential -Message "Username and password")
        }
        Export-Clixml -Path $Path -InputObject $ConfigData
    }
    return $ConfigData
}
function Get-MyCredentials {
    Param(
        [object]
        $ConfigData
    )
    if ($ConfigData.Credential) {
        # Check if creds are in config file
        return $ConfigData.Credential
    }
    else {
        # Go recreate the config file if creds aren't there.
        return (Get-ConfigData).Credential
    }
}

$Global:ConfigData = Get-ConfigData
$Global:Credentials = Get-MyCredentials -ConfigData $Global:ConfigData
Invoke-MyFunction -Credential $Credentials