Good password management practices require that you regularly change your password. You should try to change your WordPress password at least every two months.
Changing WordPress password is really easy. It is possible to change your password at the database level as well but WordPress itself provides an easier solution. In order to change your WordPress password, you need to have logged into your WordPress dashboard. Go to your site at http://yoursite.com/wp-admin and login with your username and password.
Next go to Users>Your Profile from the left side black menu.
One the page that opens, Click on Generate Password under Account Management and next to New Password
WordPress automatically generates a complex password. This password will be very hard to remember. In fact, it is impossible to remember this long and complex WordPress password. Therefore, you may enter your own password her. The new password that you want. Try to avoid simple and easily guessable passwords.
After entering your password, copy it at some safe place and then click on Update Profile button at the bottom of the page and you will have successfully changed WordPress password for your user name.