You can manage your domain's contact information from your control panel. You can enter your custom registrar information and choose to display that information. To do so please complete the below steps:
Step 1: Login to your user control panel.
Step 2: Click on Domains>My domains, then select your domain and browse to its control panel page
Step 3: Click on the contact information under the manage section
Step 4: Fill up the required information and click on save for the update to take effect.