我们一般说的发票可以说:tax invoice像购物小票可以说:receipt不好意思我们的发票一开完,请保管好您的小票于次月初到本店换票,造成您的不便,小店是在抱歉:sorry our invoice has gone,would you please keep slip in the second month beginning to change the invoice,for the inconvenience shop i'm sorry.个人的话直接拼写就可以了~单位XXXXLTD(有限责任公司) XXXX company