Not aware of any option to remove “Promo Code” language on my Editor X and Wix Stores checkout pages. Not all products, services, or brands lend themselves to promo codes. This can especially be the case with luxury or charity products.
Imagine when purchasing an iPhone or making a purchase for charity and seeing “Enter Promo Code Here” just prior to making purchase. Cheapens the customer experience. Worse more, gives the customer a feeling that they are missing out on extra savings or being charged more than necessary (even if there actually is no promo code). Often prompts an external Google search for a (non-existent) product promo code that results in distraction, frustration, and lost purchase.
Recommend making option to not have promo code language in checkout pages if there is not a promo code. Same goes for Add a Note “Special Request” option. Businesses do not always want to give customers an option for a special request that they might not be able to honor. Even if I change wording to blank field it displays live dynamic icons on checkout pages. Have option to not have this display during checkout.