bagis/app/Mail/SuccessfulPayment.php

<?php

namespace App\Mail;

use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;
use App\Donation;

class SuccessfulPayment extends Mailable
{
    use Queueable, SerializesModels;
	public $donation;
    /**
     * Create a new message instance.
     *
     * @return void
     */
    public function __construct(Donation $donation)
    {
        $this->donation = $donation;
    }

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return $this->subject("Thank you for your donation!")->markdown('emails.successfulpayment');
    }
}