1. Click on "Domains" tab.
2. Select "Renew Domains".
3. Tick the domain you wish to renew.
4. Select the number of years (eg. 1 year, 2 years etc.) you wish to renew your domain.
5. Click on the "Order Now" button.
Once the above is done, the invoice will be generated for you to renew your domain.
Alternatively, you can wait for the invoice to be automatically generated 3 weeks before the due date of your domain.