Hi @Akanrat,
Yes, coupon API is missing in the docs, I will update that.
Currently, for coupon, there are two routes,
Apply Coupon
To apply the coupon, you need to pass the code key in the request body.
Route::post('cart/coupon', 'CartController@applyCoupon');
Remove Coupon
Route::delete('cart/coupon', 'CartController@removeCoupon');
Just need to hit the route.
For more details, you can check the route file also.