If you have products with multiple variations, such as clothing or trainers then follow the guide below to add a Product Option to your variant products
1. Go to the Products page and click into the Variant product to open the product summary window. Scroll all the way down to the bottom and click on the + New Option button
2. The Product Options dropdown will show at the bottom of the page. You can either choose an existing Product Option from the dropdown menu and press the + ADD button, or create a brand new option.
3. Once you've added the new option click on the Edit icon next to the first variant
4. Under the Product Option you just added enter the option for that specific variant and hit Update. Repeat Step 3 and 4 for each variant