PDF documents are very popular and have been for many years. They can be used to store various documents, such as projects, reports, statistics, invoices and other sensitive and private content we would not really want to be freely accessible and read by just anyone. You want to give access only to the intended ones.
To secure this type of file or share it so that only authorized people can read it, you need to add a password to it. As the security features on Adobe Reader DC are paid-for, we had a look and where able to find some free PDF editors that offer the option of adding a password to files both set for reading and editing.
Of all the free PDF editors out there, Wondershare’s PDFelement is one of the most popular. It features an easy to use interface and lots of great features including creating files from different formats, merging and editing files, and crucially, enables you to protect documents with passwords.
Sejda PDF editor is a very basic and free editor but works differently from Adobe and many of the other popular editors. You can’t create PDFs from other files, and you can’t scan documents. However, if you’re only looking to make slight alterations, this is a good option. Notably, you can use it to protect your files by adding passwords and setting permission levels and restrictions.
Some people refer to Able2Extract as being a PDF file Swiss army knife. For a free piece of software, you get some very nice and sophisticated features and an easy, user-friendly interface. It can convert files both into and from PDF format and allows you to edit as well as setting 256-bit passwords for files and access levels for different users giving permission for different actions.