Inter-office, "inter-office," means between offices. Inter means between two different offices.  办公室内部，“办公室内部”指各办公室之间。内部是指两个不同的办公室之间。

So, inter-office paperwork would be things, letters, memos, 因此，办公室内部文件会是一些物品、信件、备忘录，

other business forms that you would give to another office in your company.  和一些你会给公司内其他办公室提供的业务形式。

If you are in the accounting department, you take care of the money;  如果你在会计部门，你负责保管钱；

you might send information to the sales department; that would be inter-office paperwork. 你可以给销售部门发送信息，那就是办公室内部文件。

Paperwork, "paperwork," (one word) just refers to any form, letter, memo, 文件，“文件”（一个词）是指任何形式的信件，备忘录，

anything on paper that is related to your business. Sometimes people use this expression, paperwork,  任何与你业务相关的纸张。有时人们使用这种表达，文书工作，

to describe unnecessary forms or paper forms that you have to complete that cause a lot of problems - that take a lot of time.  来描述你必须完成，但却不必要的内容。这会导致很多问题发生，它占用大量的时间。

Someone may say, "There's too much paperwork to get a visa to the United States" - a lot of paperwork. 有人可能会说：“要拿到美国签证需要填写很多（表格）文件”——大量的文书工作。