Hey maorfrommiami,
Welcome to Apple Support Communities.
When using Wallet & Apple Pay on your Mac, if the website has the option for Apple Pay when checking out, you should be able to access the payment methods linked to your Wallet. For more details, click here: Use Wallet & Apple Pay on Mac.
If the websites do not have the Apple Pay option, your credit card details can be saved if iCloud Keychain is enabled.
iCloud Keychain remembers things, so that you don't have to. It autofills your information—like your Safari and app usernames and passwords, passkeys, credit card information and security codes, and Wi-Fi passwords on any device that you approve.
To turn on iCloud Keychain on your Mac, follow the streps below or in this article: Set up iCloud Keychain.
1. Choose Apple menu > System Settings (or System Preferences).
2. Click your name, then click iCloud. In earlier versions of macOS, click Apple ID, then click iCloud in the sidebar.
3. Turn on Password & Keychain.
4. If you choose to "Approve Later" when signing in to your Apple ID, you need to approve with an old passcode or from another device when prompted. If you're unable to approve, reset your end-to-end encrypted data when prompted.
If you're experiencing a different issue, providing more details may help you get more answers.
Take care.