How to implement category in Laravel Project

There is no fixed way but I will try to guide you anyway….

First create database table for Category

public function up(): void
   {
       Schema::create('categories', function (Blueprint $table) {
           $table->id();
           $table->string('categoryname');
           $table->string('categoryslug')->unique();
           $table->timestamps();
       });
   }

Change your post table like this

basically adding this code :

public function up(): void
 {
     Schema::create('posts', function (Blueprint $table) {
         $table->id();
         $table->string('title');
         $table->text('content');
         $table->foreignId('category_id')->constrained('categories')->onDelete('cascade');
         $table->timestamps();
     });
 }

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Category extends Model
{
     use HasFactory;

    protected $fillable = ['name', 'slug'];

    public function posts()
    {
        return $this->hasMany(Post::class);
    }
}

<?php

namespace App\Models;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Post extends Model
{ use HasFactory;

    protected $fillable = ['title', 'content', 'category_id'];

    public function category()
    {
        return $this->belongsTo(Category::class);
    }
}

Now in the create.balde.php file where you create post there

<label for="category">Select Category:</label>
     <select name="category_id" id="category" required>
         <option value="">-- Choose Category --</option>
         @foreach($categories as $category)
             <option value="{{ $category['id'] }}">{{ $category['categoryname'] }}</option>
         @endforeach
     </select>

Now to view this we need to make change at

<div class="container">
        @foreach($posts as $post)

            <h1>{{$post->title}}</h1>
            <h5>{{$post->content}}</h5>
            {{ $post->category ? $post->category->categoryname : 'No Category' }}

            <hr>

        @endforeach
    </div>

{{ $post->category ? $post->category->categoryname : ‘No Category’ }}

Now to make dynamic navabr so that we can show the catefory post

Routes

// routes/web.php
use App\Http\Controllers\PostController;

Route::get('/category/{slug}', [PostController::class, 'showByCategory'])->name('category.posts');

Controller method

// app/Http/Controllers/PostController.php

public function showByCategory($slug)
{
    // Find category by slug
    $category = \App\Models\Category::where('categoryslug', $slug)->firstOrFail();

    // Get posts belonging to this category
    $posts = $category->posts()->latest()->get();

    return view('posts.category', compact('category', 'posts'));
}

navbar methods

<nav>
    <ul>
        @foreach(\App\Models\Category::all() as $category)
            <li>
                <a href="{{ route('category.posts', $category->categoryslug) }}">
                    {{ $category->categoryname }}
                </a>
            </li>
        @endforeach
    </ul>
</nav>

Category Page Blade (resources/views/posts/category.blade.php)

<h1>Posts in {{ $category->categoryname }}</h1>

@foreach($posts as $post)
    <div>
        <h2>{{ $post->title }}</h2>
        <p>{{ $post->content }}</p>
        <p>Category: {{ $post->category->categoryname }}</p>
    </div>
@endforeach