I have no problem connecting my iPhone to the PC via USB, but for some reason it uses the battery while I am using the camera to stream. Is there a setting in my iPhone 12 I need to switch to in order to allow the USB to both power the phone and transfer data?
#iPhone will not charge while plugged into USB.
tall cipher
noble spade
Make sure that there isn’t anything in the phone port. Some cables could also not be good enough for data and charging or just damaged from time. There is a USB Accessory toggle in Settings > Face ID & Passcode > Accessory.
If nothing helped try a different USB port as some ports could be damaged or not be for used for both like a laptop.
fervent schooner
To provide more information, typical USB ports on a computer do not provide enough power to charge the iPhone if it is in use.
Some desktop motherboards(and a few laptops) may specifically feature ports that provide extra power, but you are still reliant on whether the the extra power matches Apple's required protocol for charging.