Auto body filler will fix a hole in a car door, depending on the size and nature of the hole. If the hole is clean, it can be filled by an application of body filler. You must use proper backing material so the body filler can have a base to cling to. If the hole is caused by rust, then you should definitely get a roll of filler tape to which the body filler can attach to. You should remove as much of the rust as possible so the hole will not spread. You can then apply the backing tape – usually made by Bondo and with very strong glue – to the rust to prevent its spread before applying the body filler.
For more info, see Common DIY Auto Body Repair Supplies