DuitNow Transfer lets you send money instantly to your recipient's Duitnow ID or Account Number.
A DuitNow ID can be any of the following:
You may register one or more DuitNow IDs by linking them to your RHB Current Account/Savings Account. Only one ID can be linked to one account.
Find out more here.
No, you can only link to one bank account.
Yes, you can do this via 'Settings' > 'Account' > 'DuitNow ID'.