The shipping section is not showing up on my default checkout page

The shipping section and associated fields will only show up on the core checkout page if the product has been configured as a shippable item. Otherwise, this section will not display because there's nothing to ship.

The Checkout Core Page is a dynamic page. It changes based on the information embedded in purchase link SmartTags. Each Purchase_Link SmartTag is associated with a product, membership level or bundle.

If the product has been configured as shippable, then you should double-check that the [MM_Form_Section type='shippingInfo' ] and [ /MM_Form_Section ] are surrounding the shipping section on your checkout page.