Changing your password on WordPress is very simple. You can follow these simple step-by-step instructions:

1. In the Admin Panel menu, go to USERS
2. Click on your username in the list to edit
3. In the Edit User screen, scroll down to the New Password section and type in a new password in the two boxes provided. The strength box will show how good (strong) your password is.
4. Click the UPDATE PROFILE button

You can also watch the tutorial video below.

The information above was copied from Resetting Your Password.