pagination not styled in laravel 5.5

For pretty boostrap 4 pagination, simply call this:

{{ $results->links( "pagination::bootstrap-4") }}

To display the pagination links in your blade view:

{{ $posts->links() }}

Or if you need to specify Bootstrap 4:

{{$posts->links("pagination::bootstrap-4")}}

Laravel docs: https://laravel.com/docs/5.5/pagination

For Laravel 8

Laravel includes pagination views built using Bootstrap CSS. To use these views instead of the default Tailwind views, you may call the paginator's useBootstrap method within the boot method of your App\Providers\AppServiceProvider class:

use Illuminate\Pagination\Paginator;

public function boot()
{
    Paginator::useBootstrap();
}

Laravel docs: https://laravel.com/docs/8.x/pagination