Resetting the backend admin password will be something you will often do with your OpenCart store. It is possible that you will forget the password or you want to strengthen the password or you just want to change it after giving it out to someone else. There will always be some need to change this very important password.

The following tutorial will take you through how to change your admin password in OpenCart.

Log into cPanel and click on phpMyAdmin
Open the database that is connected to your OpenCart store.
Find the "user" table
Edit the user with the username "admin" and change the password field to 5f4dcc3b5aa765d61d8327deb882cf99. This string or hash changes the password to "password" (without the quotes)
Click "Go"

Now, attempt to log into the OpenCart Dashboard with your new password

You will need to change the password to a strong once you login to your OpenCart admin area.one as soon as possible


Source: https://www.todhost.com/knowledgebase/725/How-to-reset-the-admin-password-in-OpenCart.html