This article will demonstrate how to display a phone number field on the checkout form for customers to fill out. This will improve the prospects for future remarketing.
Step by Step Tutorial
From your ShopBase admin, go to Online Store > Themes. Select the theme you want to edit and choose Customize.

Select Checkout page from the dropdown menu.

Select Account & forms section.

In Form options > Shipping address phone number section, choose Required (to require your customers to fill in) or Optional (to ask your customers to fill in if they want)

Click Save once finished.