You can change your password under User Settings > My Profile.
Steps to Change Your Password
From the home screen, tap the hamburger menu (☰) in the top left corner.
Scroll down and select User Settings.
In the MY PROFILE section, tap manage my profile.
Tap the Change password button.
You will be directed to a page where you can enter your current password, a new password, and confirm your new password. Be sure to tap the Change Password button to save your changes.