add extra options during checkout of marketpress, such as embroidery

How can I handle adding custom embroidery, for example, to a purchase? So the item is bought for $30 and the customer wants Embroidery (+ $5) and some special notes to where to place it?

Nothing stood out to me on the Product page (though I do see 'this product has multiple variations').

I also do not see this feature available on the plugin page

Thank you for your always excellent support and direction!