htmlspecialchars() expects parameter 1 to be string, array given

I have three tables. Sales, Services, and Customers. I've set up the relationship between the three tables. When I save a sale in the database, the id of the customer and service is saved. Currently, I have been able to get the related data from the customer and service table based on the sales table. but I have a problem displaying them in my blade file.

This is my sales controller

    public function index()
    {
        $sales = Sale::all();
        
        foreach($sales as $sale){
            $customer_car_reg_no[] = $sale->customer->car_reg_no;
            $service_name[] = $sale->service->name;
        }

        return view('adminlte.sales.index', compact('sales', 'customer_car_reg_no', 'service_name'));
    }

When i remove the "[ ]" attached to the variables, it only displays the last item in the array. When i leave them there i get this error

htmlspecialchars() expects parameter 1 to be string, array given (View: C:\code\Valet\resources\views\adminlte\sales\index.blade.php)

This is my blade file

<table class="table table-striped projects">
              <thead>
                  <tr>
                      <th style="width: 1%">
                          S/N
                      </th>
                      <th style="width: 20%">
                        Car Reg No
                      </th>
                      <th style="width: 20%">
                        Service(s)
                      </th>
                      <th style="width: 20%">
                        Washed By
                      </th>
                      <th style="width: 10%">
                        Date
                      </th>
                      <th style="width: 8%" >
                        Total
                      </th>
                  </tr>
              </thead>
              <tbody>
                @foreach($sales as $sale)
                  <tr>
                      <td>
                        {{$loop->iteration}}
                      </td>
                      <td>
                        {{$customer_car_reg_no}}
                      </td>
                      <td>
                        {{$service_name}}
                      </td>
                      <td>
                      {{$sale->washer}}
                      </td>
                      <td>
                        {{$sale->date}}
                      </td>
                      <td>
                        {{$sale->total}}
                      </td>
                  </tr>
                @endforeach
              </tbody>
          </table>

This is my migration file

    public function up()
    {
        Schema::create('sales', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->unsignedBigInteger('customer_id');
            $table->foreign('customer_id')->references('id')->on('customers');
            $table->unsignedBigInteger('service_id');
            $table->foreign('service_id')->references('id')->on('services');
            $table->date('date');
            $table->string('washer');
            $table->decimal('total', 8, 2);
            $table->timestamps();
        });

    }