Is it possible to perform a partial capture of funds on my Shift4Shop store?
Only if the capture is less than the authorized funds and only if your payment gateway allows for the Authorize Only setting.
The Authorize Only setting available on some payment gateways allows you to authorize the card for the amount specified on the order. As you process the order, you can capture funds before shipping the order out. Typically, the capture is for the same as the authorized amount. However, if the order has changed in some way that would recalculate the balance to be less than the authirized amount, then your capture will be for that updated amount.
In other words, let's say your shopper orders two units of an item by mistake when they intended to just order one. The Authorize Only setting on your payment gateway authorized the card for the price of the item x2 (because they selected 2 during the order).
As you process the order, you can update the it so that it is only for 1 unit. This can be done by clicking on the unit number (in the order) and updating it to the necessary number. Once you save the order, the store will re-calculate the balance to reflect the new amount.
In this case, when you capture the funds for the order, it will be for the updated amount.