Macbook charge with an iPad charger
The iPad charger is 10 W and the MacBook charger is 29 W, so you would really be limping along from a power source that's not sufficient. I haven't tested, but my guess is the MacBook won't even try to charge from that small power source.


https://support.apple.com/en-us/HT201700


The second hurdle you will face is that you'll need a charging cable to go from the iPad charger's USB A port to the USB C port. This basically will connect the 4 wires the iPad charger uses to the 24 pins that the MacBook expects.





I wouldn't count on this doing anything and instead look for an Apple Adapter or third party adapter that adheres to the USB Power Delivery specification - Apple specifically lists that this is supported by the MacBook.