Hi,
I know that but if one user have 3 discount code, he can use all of them on one cart.
I want to if a user use a discount code, after that “Do you have promotion code?” on cart will disable.
There are cases people would allow their customers to use several discount codes, so we can’t change the feature.
See attached pic, you can set vouchers to be not compatible with each other to achieve what you needed.