You can change you password from within the HulloMail app.

iPhone:

1. Using the HulloMail app, select Menu -> Account -> Password, PIN

2. Enter your Old Password

3. Enter New Password

4. Confirm New Password

5. Click Save

Android:

1. Using the HulloMail app, select Menu -> Settings-> Account -> Password, PIN

2. Enter your Old Password

3. Enter New Password

4. Confirm New Password

5. Click Set Password