How can I add a new address to the service center list?

You can simply add another Text field to your form, and enter the new address into the newly created Text field. Here's how:

1. Just drag the Text field to your form. After that, you can insert the Service Center details.

2. You can add a city here in the Options button. Just select the Select your City field and then click the Options button.

Also, If you want to put a conditions to the added address field. Please check this guide: https://www.jotform.com/help/57-Smart-Forms-Using-Conditional-Logic

Hope that helps. Thank you.