First invoice implementation.

app/Http/Controllers/Api/InvoiceitemController.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace App\Http\Controllers\Api;
+
+use App\Http\Controllers\Controller;
+use App\Models\Invoice;
+use App\Models\Invoiceitem;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+
+class InvoiceitemController extends Controller
+{
+    /**
+     * Display a listing of the resource.
+     */
+    public function index(Invoice $invoice): JsonResponse
+    {
+        return response()->json($invoice->items);
+    }
+
+    /**
+     * Store a newly created resource in storage.
+     */
+    public function store(Request $request, Invoice $invoice): JsonResponse
+    {
+        $itemData = $request->validate([
+            'amount' => 'required|numeric|min:0',
+            'discount' => 'numeric|nullable',
+            'tax' => 'required|numeric|min:0',
+            'price' => 'required|numeric|min:0',
+            'total' => 'required|numeric|min:0',
+            'name' => 'required|string',
+            'description' => 'nullable|string',
+
+        ]);
+
+        $item = $invoice->items()->create($itemData);
+        return response()->json($item);
+    }
+
+    /**
+     * Display the specified resource.
+     */
+    public function show(Invoiceitem $invoiceitem)
+    {
+        //
+    }
+
+    /**
+     * Update the specified resource in storage.
+     */
+    public function update(Request $request, Invoiceitem $invoiceitem)
+    {
+        //
+    }
+
+    /**
+     * Remove the specified resource from storage.
+     */
+    public function destroy(Invoiceitem $invoiceitem)
+    {
+        //
+    }
+}