Job costing is specific to individual, specialized jobs while process costing applies to larger scale processes and standardized products. Process costing is typically used by companies that mass produce products that are identical.
An interior designer remodeling a house for a client would use job costing to track costs since each design project is different.
A cereal manufacturer would use process costing to determine the cost of each cereal box since ingredients, materials, and the end product are the same across the board.