Laravel Blade add parameter to wildcard URL

I am working with Laravel 5 and I have a URL which is something like this:

<a href="/admin/whmcs-clients-invoices/" target="_blank">
    @if($payment->inv_id != null || $payment->inv_id != "")
        
    @else
        
    @endif
</a>

Is there a way that I can add a parameter like ?pay= in the URL using blade? I tried adding it, but it seems the parameter can't be called or doesn't show up in the redirected page.

via Chebli Mohamed