On the top right corner of the website homepage, you will find your profile details. To check the details, you need to click on your name.
In this section, you will find:
Settings: From this section, you will have the option of changing password. As you click on Change Password, you will be directed to a new screen where you will have to enter the current password and then enter the new password. (You can change password to a specific length)
In the app, you will find the option to Change Password under Settings section available on left menu which will be displayed after you click the icon given at top left.