Hi Ryan! Under the "Profile" section on the Motorist app, it will reflect the existing vehicles which you have added and also gives you the option to add an additional vehicle :) Feel free to reach out if you are still having issues.

Please note additional steps due to changes in LTA:

Input Access code, you may retrieve the Access Code by logging in using your Singpass via the following link: https://onemotoring.lta.gov.sg.