If a doctor accepts HMO, you will be able to see it on the doctor's booking page.
Select Yes for "Are you using HMO for this consultation" (If it's not visible, the your doctor doesn't want to accept at the moment)
At the end of the booking process, you will be asked about your Member ID, LOA Code and the eLOA file. You will also be shown extra instructions if your doctor added some more instructions.
Fill it up and upload the file and click Book Appointment to finish
Note: Your HMO provides the member ID. You can contact your HMO to request for the LOA.