Image forming apparatus, method for controlling the same, and non-transitory computer-readable storage medium

An image forming apparatus includes a controller configured to start feeding a sheet from a feeding unit without confirming a presence or absence of an insert sheet to be inserted before the sheet when an amount of insert sheets stacked on a stacking tray as a feed source is higher than a predetermined amount. In a case in which the amount of the insert sheets on the stacking tray is lower than the predetermined amount, the controller starts feeding a sheet from the feeding unit without confirming a presence or absence of the insert sheet when another stacking tray on which an amount of insert sheets is higher than the predetermined amount is present, and the controller starts feeding the sheet from the feeding unit after confirming the presence or absence of the insert sheet when the other stacking tray is absent.