shipping-portal/app/Models/Package.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasOneThrough;
use Illuminate\Database\Eloquent\Relations\MorphTo;
use Illuminate\Database\Eloquent\SoftDeletes;

class Package extends AbstractModel
{
    use SoftDeletes;

    protected $table = 'packages';

    /**
     * @return BelongsTo
     */
    public function packingList(): BelongsTo
    {
        return $this->belongsTo(PackingList::class, 'packing_list_id');
    }

}