How to reset the password and apply restrictions for email accounts

From your cPanel account, access Email Accounts under the Email category.

Next to the desired address, click "Manage" button.

In the New Password field enter the password of your choosing or generate a random password with the Generate function of cPanel. To save the change click on "Update Email Settings" button.

OPTIONAL: The Generate function of cPanel can help to generate random passwords, respecting certain criteria. The criteria can be reviewed and selected by clicking on the Generate symbol on the right. Also, to see the password, the symbol to the left of the "Generate" button must be unchecked.

From the same page you can suspend sending and receiving emails, or even log in to that email account. Under Restrictions category, check the options you want to implement, then click "Update Email Settings" to update your changes.