To make inventory tracking easier, you can group different combinations of product option variants under option combinations. For example, clothes come in various colors and sizes. Option combinations allow you to track separately, how many blue XL-sized T-shirts and white M-sized T-shirts you have.
Only Check box, Select box, and Radio group options that have the Inventory checkbox ticked can be a part of a combination.
In the Administration panel, go to Products → Products.
Click the name of the product you want to edit.
(optional) Set the Inventory setting to Track with options and click the Save button. This will allow you to track product quantity for each option combination separately.
Switch to the Options tab and click Option combinations. This will take you to the list of option combinations for this product.
The Option combinations button appears only if the product has options.
Click the + button on the right to add combinations manually.
You can automatically create all possible option combinations for the product. To do that, click the gear button instead of +, and choose Rebuild combinations. This won’t overwrite the existing combinations.