Login to your OpenCart admin panel. In your browser address bar type http://yourdomain.com/admin. If you have installed your Opencart under a subfolder “store” for an example the above URL will change to http://yourdomain.com/store/admin Login using your username and password.
Navigate to System > Settings and click Edit button
Type your email address to E-Mail field and Save the changes.
Click Edit button and select Mail tab
You should see following options:
Email settings are server specific so it is better to contact your hosting provider and ask them which settings you should use.
Configure email settings and save the changes.
Go to Contact page and submit email form to test if the settings are correct.
Feel free to check the detailed video tutorial below:OpenCart 1.5.x. How to manage email options,