Hey there Applestorecreditcardinfo,
Thanks for reaching out to the Apple Support Communities.
To get started, when making the online purchase, did you choose to make the payment with Apple Pay, or were you seeing this payment method as an option to automatically fill in your information when making the purchase?
If you were seeing the option to automatically fill in this information for you, you can use the steps in the following resource to see if that payment method is set up to AutoFill when making a purchase in Safari: Automatically fill in your information in Safari on iPhone - Apple Support
Set up AutoFill
You can save your personal information or credit card number on your iPhone to speed up filling in online forms and making purchases.
1. Go to Settings
> Safari > AutoFill.
2. Do any of the following:
- Set up credit card info: Turn on Credit Cards, tap Saved Credit Cards, then tap Add Credit Card. Enter your credit card information into the fields provided or tap Use Camera to enter the information without typing.
Let us know if that's able to help.
Take care!