digital_college/src/server/app/Models/Courses.php

<?php

namespace App\Models;

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

class Courses extends Model
{
    use HasFactory;
    protected $visible =['name','price','isActive','email','period','level','hours','teachers'];
   public function teachers(){
       return $this->belongsToMany(Teachers::class);
   }
}