In the Preference Builder Properties panel, choose from four format options for how end users select channel types.
Where: This change applies to Lightning Experience and Salesforce Classic in Enterprise, Performance, Unlimited, and Developer editions.
Who: This change is available to users with the Privacy Center add-on subscription.
How: Create or edit a form in Preference Builder. In the Properties panel, go to the Channel Types section. From the dropdown list, select an option to determine how the channel type options appear on the form.
Customize Channel Type Selections on Preference Forms (salesforce.com)