Hi there! To allow customers to change the verification code during checkout in OpenCart, you'll need to override the default template file.
Specifically, edit the following file:
catalog/view/theme/your_theme/template/checkout/verification.twig
In there, you'll want to replace the verification input with something like this:
<input type="text" name="verification" value="{{ verification }}" />
This will make the verification code field editable, allowing the customer to update it.
You'll also need to disable verification code validation on the server side. You can do this by editing system/library/cart.php and commenting out or removing the code that checks the verification hash.
A doctor’s note template is a pre-formatted document that can be used as a starting point to create a doctor’s note
Just keep in mind that this will lower security at checkout, so I only recommend it if you have other measures in place like HTTPS forced, etc.
Let me know if you have any other questions!