Watch the short video below, for detailed instructions, in case you forgot your password.
The steps in detail:
You can reset your password provided that you have your registered mobile phone number with you.
Select the Log in link from the Viva Wallet website.

Click the I forgot my password link and follow the instructions.

Enter the registered telephone number and select Reset Password

You will receive a 6 digit code to your registered telephone number,
You enter it as below and select Continue

You create a New Password and select Complete

You see the message for successful change:
