Follow below steps to change the Wordpress Password:-
1. Log into cPanel.
2. Under Software/Services, click on QuickInstall.
3. At the top of the page, click My Installs.
4. Locate the installation you wish to modify.
5. Click Reset Password.
6. Select the username you wish to change the password for from the drop down box, then enter a new password.
7. Click the Reset Password button to change the password for the selected user.
Method 2:- Set Password manually by PHPMyAdmin
1. Log into cPanel.
2. Under Databases, click phpMyAdmin.
3. Click on the WordPress database (if you installed this through QuickInstall, this will be named wrdp#) from the left panel list.
4. Click wp_users from the left panelist.
5. Under user_login you will see the list of registered users. Under the user whose password you wish to reset, click edit.
6. Under the user_pass column, clear the value on the far right and replace with what you would like the password to be.
7. In the Function drop-down menu, select MD5.
8. At the bottom of the page, click GO.