Short Description
In Product overview > Click Short Description

Setup Short Description by Metafields?
- From your Shopify admin, go to Settings -> Custom data 
- Click Products → Add Definition. 
- Please enter correct Namespace and Key as we noted below. 
Name: Short Description or any name Namespace and key: info.shortdesc Select content type: Text

How to insert content for Product Metafields?
- From your Shopify admin, go to Products -> All products. 
- Find and choose the product that you want to edit. 
- In the Metafields, please insert content for "Short Description" field. 

Or you can access link 'Enter content for each product here.' => You can enter short description for each product