Inserting and updating data from dynamic form properly

So far, I have found answers in here and never needed to ask anything. But this issue is really bugging me. Here is the situation. I have a dynamic invoice form. Posts from the form will be saved to two different tables

1. invoices(where details for invoice is stored like member_id, discount, duedate, remarks and the timestamps) 2.invoiceitems(invoice_id, itemdescription, quantity, rate, timestamps)

To achieve this, here is my method to store invoice

   public function store(InvoiceRequest $request)
{

    //get necessary details for invoice table
    $datainvoice = array(
    'member_id' => $request->input('member_id'),
    'duedate' => $request->input('duedate'),
    'discount' => $request->input('discount'),
    'remarks' => $request->input('remarks'),
    //'gtotal' => $request->input ('gtotal'),
    );

    //save result of invoice
    $resultforinvoice = Invoice::create($datainvoice);


    // ready all data of invoice items
    $datainvoiceitem = array(
    'description' => $request->input('description'),
    'rate' => $request->input('rate'),
    'quantity' => $request->input('quantity'),
    'invoice_id' => $resultforinvoice->id,
    );


     // insert invoice along with invoice_id
    Invoiceitem::create($datainvoiceitem);
    return redirect('members');

}

Additional Information:

Relationship between members and invoices:: member-has-many-invoices, invoice-belongs-to-single-member

Relationship between invoice and invoiceitems:: invoice-has-many-items, an-item-belongs-to-one-invoice

partial of the dynamic form:

<td>  1   </td>
<td><textarea type="text" name='description[0][description]'   class="form-control"/></textarea> </td>
<td><input type="text" name='quantity[0][quantity]'  class="form-control"/></td>
<td> <input type="text" name='rate[0][rate]'  class="form-control"/>   </td>

Errors im receiving right now Argument 1 passed to Illuminate\Database\Grammar::parameterize() must be of the type array, integer given, called in C:\xampp\htdocs\study\vendor\laravel\framework\src\Illuminate\Database\Query\Grammars\Grammar.php on line 719 and defined

Update: when i try to return the inputs for invoiceitems, i get an array like below {

"description": [
    {
        "description": "desc1"
    },
    {
        "description": "desc2"
    }
],
"rate": [
    {
        "rate": "11"
    },
    {
        "rate": "22"
    }
],
"quantity": [
    {
        "quantity": "1"
    },
    {
        "quantity": "2"
    }
],
"invoice_id": 41

}

Thanks in advance, This is my first application in Laravel. Im still learning, please dont mind if what im asking is stupid. This website has helped me alot

Ashish Aryal