How can I enable the coupon input box on the customer order pay page?

When a customer clicks on the link to go to their payment page, the ‘Have a Coupon?’ input box does not appear. I haven’t made any adjustments to the templates.

Do you have any ideas on how I can make the coupon input box visible on the customer payment page?

The location I am referring to is:

/checkout/order-pay/<order_id>/?pay_for_order=true&key=<order_key>
Screenshot : https://prnt.sc/-T4dnbDTuPTW