Click on Store on the left side of your home page. And scroll down to choose Product Badges.
​
​
​

​
​

Select the badge of your choice from All
​
​
​

​
​

You can change the color, position (top left, top right, bottom left, and bottom right), and size (S, M, L) of the badge by clicking on the options below the product.
​
​
​

​
​

Click on Update Store to apply the badge to the chosen products
​

​

​