stagfe2/app/Models/Customer.php

<?php

namespace App\Models;

# use Illuminate\Database\Eloquent\Model;

class Customer extends Model
{
    protected $table = 'customer';

    public function client() {
        return $this->hasOne(Client::class, 'id', 'client_id');
    }

    public function company() {
        return $this->hasOne(Company::class, 'id', 'company_id');
    }
}