So you created a profile on https://www.usvisascheduling.com/ (which is linked from the ustraveldocs website), did everything below and you're saying there's no option to select the payment for a K-1 visa?
Step 2
Select the “Start Application” option on the left-hand side of your screen, and proceed in answering the questions provided. We advise that you read carefully and respond accordingly to the questions.
Step 3
On the Payment Options page, read the Disclaimer Notification AND verify that the number and amount of visa fees you are paying for are correct and that they match the number of applicants in your profile and the visa type you are applying for before selecting the “Submit” button.
Step 4
Print the payment instruction page and bring a copy to RCBC branch. Hand over the copy to RCBC branch and make your consular visa application fee payment.
After making the payment and before leaving RCBC branch, please check the validated receipt issued by RCBC and make sure the reference number and amount paid matches the details in your payment instruction copy. If incorrect please ask RCBC to have it corrected right away.