Here's a guide on how to add your Visa card to your Apple Pay account.
Open the Wallet app on your phone and tap the "+" icon
Select "Debit or Credit Card," and tap on continue
Enter your card name and number
Enter your card expiry date and security code
Tap on continue after filling in your card details and verify with the OTP sent to your email as prompted.
This process adds your card to your iPhone, Apple Watch, iPad, or Mac, enabling tap-to-pay purchases after you link your card to your wallet.