Focus and exposure are maintained where the blue AF point is displayed while you press the shutter button halfway. This helps you avoid missing shots of subjects in motion.
For assistance with Bluetooth pairing between the camera and a smartphone, please see this article: https://support.usa.canon.com/infocenter/index?page=content&id=ART173357
When the camera and iPad are connected via Wi-Fi, the images on the camera can be imported to the iPad and displayed in Photo Professional Express. The two ways to import images are as follows.
Enable Helps avoid missing sudden photo opportunities, because the camera constantly focuses on subjects until you press the shutter button halfway. Disable Conserves battery power, because the camera does not focus constantly. However, this may delay focusing.