This option can be enabled if there are variations of your product that command unique prices for each of those variations.
For example, a t-shirt that is being sold may have a unique price for a small version, medium and large version.
To enable this option, simple click the switch on the right side to enable and show the tick in a green box which means it is active. By default this is disabled.
By enabling this option you will see the option to add those product formats in and to set the price for each one.
Note: By enabling this option, any price you set in the main product details will be overwritten by the options here.