Step 1: You need to click Profile icon (Top right).
Step 2: Click on “Change 6-digit PIN”
Step 3: Enter your current 6-digit PIN.
Step 4: Enter your new 6-digit PIN.
Follow the guide here https://m.youtube.com/watch?v=tcyIjnNqvMQ
If you forgot your 6-digit Pin, follow the guide here: https://youtu.be/Om_hCR9VAQ4