With WHM/cPanel, you might find that at times you might want to reset your cPanel password for purposes such as best practice or routine security. You can do so from both the WHM & cPanel accounts. If you do not have the root password, then you will need to reach out to your hosting provider for assistance in resetting the root password.
*Please keep in mind cPanel support is unable to change the login credentials for end-users for security reasons.
From WHM Home » Account Information » List Accounts :
Select your cPanel account, and next to the account, you can drop down settings with " +, " from there, you see the option to " Change Password," and you can input your new password.
From cPanel Home » Preferences » Password & Security :
You will need to input the Old Password, followed by the New password. Once you fill out these fields and make sure the password is passing the required strength. Save the password.
Note: Changing your password, you will end your current session. And be required to log in, once again with the new password.
The following documentation will provide information additional details on how to reset passwords: