How to remove Notice error on Opencart 2 on Checkout Page?

Question

opencart

Here are the Notices:
Notice: Undefined index: account in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 313
Notice: Undefined index: account in /home/site/www /system/storage/modification/catalog/controller/checkout/checkout.php on line 323
Notice: Undefined index: account in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 328
Notice: Undefined index: account in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 332
Notice: Undefined index: account in /home/website/www/system/storage /modification/catalog/controller/checkout/checkout.php on line 336
Notice: Undefined index: firstname in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 383
Notice: Undefined index: email in /home/website/www/system/storage/ modification/catalog/controller/checkout/checkout.php on line 384
Notice: Undefined index: telephone in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 385
Notice: Undefined index : firstname in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 393
Notice: Undefined index: address_1 in /home/site/www/system/storage/modification/catalog/ controller/checkout/checkout.php on line 394
Notice: Undefined index: country_id in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 395
Notice: Undefined index: zone_id in /home/site/www/system/storage/ modification/catalog/controller/checkout/checkout.php on line 396
Notice: Undefined index: country_id in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 400
Notice: Undefined index : zone_id in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 422
Notice: Undefined index: firstname in /home/site/www/system/storage/modification/catalog/ controller/checkout/checkout.php on line 440
Notice: Undefined index: address_1 in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 441
Notice: Undefined index: country_id in /home/site/www/system/storage/ modification/catalog/controller/checkout/checkout.php on line 442
Notice: Undefined index: zone_id in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 443
Notice: Undefined index : firstname in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2799
Notice: Undefined index: address_1 in /home/site/www/system/storage/modification/catalog/ controller/checkout/checkout.php on line 2801
Notice: Undefined index: zone in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2802
Notice: Undefined index: country in /home/site/www/system/storage/ modification/catalog/controller/checkout/checkout.php on line 2804
Notice: Undefined index: address_format in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2806
Notice: Undefined index : firstname in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2829
Notice: Undefined index: address_1 in /home/site/www/system/storage/modification/catalog/ controller/checkout/checkout.php on line 2830
Notice: Undefined index: country_id in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2831
Notice: Undefined index: zone_id in /home/site/www/system/storage/ modification/catalog/controller/checkout/checkout.php on line 2832
Notice: Undefined index: country_id in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2835
Notice: Undefined index : zone_id in /home/site/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 2836
Notice: Undefined index: payment_method in /home/site/www/system/storage/modification/catalog/ controller/checkout/checkout.php on line 2869
Notice: Undefined index: comment in /home/website/www/system/storage/modification/catalog/controller/checkout/checkout.php on line 3104
File /checkout.php
codepad.org/4TGUY61f

Answer 1

It looks like you removed half of the fields from the checkout, so an array comes to the controller from the form, without them.
Options 2.
1. On the front, make invisible fields with default values
​​2. In the controller, check the existence of the key according to the list of errors.