Step 1 - Log In
Log in to your Joomla Administration area. You will usually find your Admin area by adding /administrator to your domain name - for example, www.yourdomain.com/administrator .
Step 2 - Go to the Joomla User Manager.
In the main menu, go to Users > User Manager.
Step 3 - Search for the User
Enter part of the user's name in the Search Users box and click Search. Then click on the user's name.
Step 4 - Change the Password
Enter a new password in the Password field; enter it again in the Confirm Password field.
Step 5 - Save the User
Finally, click Save & Close.