Invoice
responsibility	collaborator(s)
format the invoice

For handling each responsibility, will this class need to use another class?

The invoice format includes an address. So the Invoice class may need to use the Address class.

Invoice
responsibility	collaborator(s)
format the invoice	Address

Similarly, the format invoice responsibility will need to use the LineItem class - the Total for a Line Item will be the responsibility of the LineItem class. The Amount Due will be computed.

Invoice
responsibility	collaborator(s)
format the invoice	Address
	LineItem