LaravelApp/app/Models/Tag.php

<?php

namespace App\Models;

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

class Tag extends Model
{
    use HasFactory;

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

    protected $casts = [
        'created_at' => 'datetime',
        'updated_at' => 'datetime',
    ];

    // Связь многие-ко-многим: тег может быть у многих заявок
    public function submissions()
    {
        return $this->belongsToMany(Submission::class, 'submission_tag');
    }
}