How to merge protected PDFs?
如何合并受保护的 PDF？
In order to combine secure files, you need to know the passwords. If your files are not protected, PDF Extra allows you to add up to two passwords and industry-standard encryption to ensure top-notch security of all your files.
要组合安全文件，您需要知道密码。如果您的文件没有被保护，PDF Extra 允许您添加最多两个密码和行业标准加密，以确保所有文件具有一流安全性。