php - How to make userEmail the foreignkey connect to the emailId in Tbluser model

one text

Solution:

App\Models\Tbluser - https://laravel.com/docs/7.x/eloquent-relationships#one-to-many

use App\Models\Tblbooking;

class Tbluser 
{
  public function bookings() 
  {
    return $this->hasMany(Tblbooking::class, 'userEmail', 'EmailId');
  }
}

App\Models\Tbluser - https://laravel.com/docs/7.x/eloquent-relationships#one-to-many-inverse

use App\Models\Tbluser;

class Tblbooking
{
  public function user() 
  {
    return $this->belongsTo(Tbluser::class, 'EmailId', 'userEmail');
  }
}

I would suggest refactoring your code and calling models User and Booking. You can use protected $table to define table that model should use, i.e. protected $table = 'tbl_bookings';.

use App\Models\User;

class Booking
{
  protected $table = 'tbl_bookings';

  public function user() 
  {
    return $this->belongsTo(User::class, 'EmailId', 'userEmail');
  }
}

Also it might be of benefit to have a separate table where you can store all your emails, to follow 3NF (https://en.wikipedia.org/wiki/Third_normal_form#:~:text=Third%20normal%20form%20(3NF)%20is,in%201971%20by%20Edgar%20F.). It's also a common practice to use snake case to name columns.