Yes! If you provide services to clients globally, and you would like to collect their country code, you may enable this feature. Here are the steps to do so:

How to Add the Country Code Selection

1. Navigate to Settings > Business Info 
2. In the Contact Info section select the box My clients have a different country code
3. Click the "Save" button found at the top of the page

Enabling this option will add a country code drop-down list to the phone number field on the scheduling form.