For Desktop and Browser clients: To access, Go to User Settings, click on the cogwheel in the client's lower left corner. Click the Change Password button on the My Account page, then follow the on-screen instructions.
For Mobile clients
Apple iOS: To access User Settings, click on your user avatar in the lower right corner. Choose Account next, then Password, and then follow the directions.
Google Android: To access, Go to User Settings, click on your user avatar in the lower right corner. Choose Change Password under My Account, then follow the on-screen directions.