You can create different types of expenses, for example mileage and food allowance, and specify which ones workers are allowed to claim against a placement.
Some placements might allow workers to claim accommodation, whereas other will not. Also, some types of expense might be chargeable, and some will have a special tax category.
In order to specify whether a placement allows certain types of expense to be claimed by the worker, you first have to define expense types and expense template groups.
An expense type is the individual expense, such as mileage.
An expense template group is the range of expense types that are applicable to the placement.