Whether you can combine several discount codes in one order depends on the respective conditions of the provider. In most cases, it is not possible to redeem several discount codes at the same time, as providers often only grant one discount per order.
However, there are exceptions:
Some providers allow discount codes to be combined with already reduced items.
Some stores offer special promotions where several discounts can be combined.
Discount codes for shipping costs can sometimes be used in addition to another discount code.
To be sure, please check the offer conditions directly on the offer page. If you are unsure or receive an error message, you can assume that further redemption is not possible.