WordPress Manager is a plugin for cPanel which most of the hosting companies provide out of the box for their clients. This plugin can be used to install/remove and modify the wordpress installations. WordPress Manager Uses wp-cli at the back and provides user interface integrated into the cPanel. WordPress manager automatically upgrades the wordpress installations to keep your website secure and fast.
To modify the password you need to login to the cPanel and navigate to the WordPress Manager. Which is usually at the end of the screen as shown in image below.
This Screen Shows all wordpress installation under that account. You can click on the Manage button against the installation which you want to manage.
On this screen, You can see different options, which includes backups and enabling/disabling automatic updates. Because we are going to change the admin password, we will click on on Admin button on left side bar.
On Above screen you will see the option to change User password. Click on that button and use new password as shown in below image.