Please follow the steps below toadd a payment method on Starbucks online.
Open the website on your desktop computer or laptop, then click Sign In.
Now, sign in with your username or email address and password.
Once you’re signed in, you will see your Account profile at the upper-right corner of the screen. Click on Account.
On the drop-down list, you will see an option that says Payment Methods. Click on Payment Methods.
At the middle part of the page, you will see an option that says Add Credit/Debit Card. Click on Add Credit/Debit Card.
Now, enter the billing address of your credit/debit card. Then, click on Continue.
Enter all the required information. Then, click on the tick box beside Make this my Default Payment Method to make this card your default payment method.
After entering all the required information, click on Save.
And now, you have successfully added a payment method on Starbucks online.