Can the processing fee invoice be used on the linen washing invoice?

Of course. The processing fee invoice can be used in the invoice for linen washing, because some processing fees may be involved in the process of linen washing. For example, washing linen may require dyeing, ironing, mending and other processing procedures, and these processing procedures all need to pay corresponding fees. Therefore, the invoice for washing linen can include processing expenses to reflect the actual costs and expenses.