For example: http://yourdomain.com/admin
In case your OpenCart is installed in a directory (for example "shop") you need to type http://yourdomain.com/shop/admin
Enter your administrator user name and password and click the login button.
The administrator user name and password are selected during the initial OpenCart installation.
Once logged in go to System » Settings in the navigation menu.
This page allows you to configure the general settings for your online shop.
In the "General" tab you can set the Store name, Store URL, Store Owner information and the contact e-mail.
Don't change the Store URL unless you have just moved your OpenCart store from another host provider or to another directory.
The "E-Mail" text box is important as this is the email address to which OpenCart will be sending you notifications about all new incoming orders. Make sure you have written a valid email address and you have access to that address.
Once you have finished making changes to the text fields click on the "Save" button to apply the changes you made.