If there’s no K1FTP letter you can use the response from the public inquiry form.
When your case changes to "In-Transit", ideally the petitioner receives the K1FTP via email within few hours. My fiancé found ours in Spam/Junk folder. 14 days later the beneficiary will receive the hard copy.
Bring the following documents:
Vaccination records – original and two (2) photocopies, including the COVID-19 vaccine certificate, if vaccinated
Visa Interview Appointment Letter – I didnt had one so I copied and signed a waiver at SLEC
Letter with Case Number – one (1) photocopy - I used the public inquiry tool response with my case number
Confirmation for K Visa applicants