If you're logged out of your account and can't remember your password, you can request to reset it from the login screen.
If you're able to log into your account and know your current password, follow these steps to change it from your Settings:
Profile button
or your
Profile Photo
from the bottom right to go to your Profile.
Options
button from the top left to go to settings.
Locate and Tap on Change Password option.
Enter your current password and then enter your new password in the given fields.
Tap done