What happens when I pay at a merchant enrolled in Mastercard ID Check? Do I have to perform additional operations?

When you buy online from a merchant enrolled in 3D Secure, your card will be automatically recognized.
After you have entered the card details on the merchant's page, you are automatically redirected to the 3D Secure page, where you are asked, in the first step, to enter an OTP code received on the number declared to the bank.
After entering the code, in step two, you must enter a static password that you set at the first online payment made with that card, at a merchant where 3D Secure verification is required. The static password will be valid for 90 days from the date it is set.

After confirming the payment through the OTP code received via SMS and the static password, you must return to the merchant's page to check if the payment was successful.